UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K/A

AMENDMENT NO. 1

ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2004

Commission file number: 1-16735

Penn Virginia Resource Partners, L.P.

Three Radnor Corporate Center, Suite 230

100 Matsonford Road

Radnor, Pennsylvania 19087

Registrant’s telephone number, including area code: (610) 687-8900

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act:

None

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15 (d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of the registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.    x

Indicate by check mark whether registrant is an accelerated filer (as defined in Rule 12b-2 of the Act).    Yes  x    No  ¨

The aggregate market value of common units held by non-affiliates of the registrant was $327,232,978 as of June 30, 2004 (the last business day of its most recently completed second fiscal quarter), based on the last sale price of such units as quoted on the New York Stock Exchange. Shares of common units held by each director and executive officer and by each person who owns 10 percent or more of the outstanding common units or who is otherwise believed by the Company to be in a control position have been excluded. This determination of affiliate status is not necessarily a conclusive determination for other purposes.

As of February 24, 2005, 12,338,458 common units and 5,737,410 subordinated units were outstanding.

DOCUMENTS INCORPORATED BY REFERENCE:

None

EXPLANATORY NOTE

We are filing this Amendment No. 1 on Form 10-K/A to our Annual Report on Form 10-K for the fiscal year ended December 31, 2004 that was originally filed on March 1, 2005 (the “Original Filing”) to amend Part III, Item 11, on page 65 of the Original Filing as disclosed herein. Generally, we have amended the Summary Compensation Table included in Item 11 to (a) disclose the values of restricted unit awards under the heading “Restricted Unit Award(s)” rather than under “Other Annual Compensation” and to reflect the values of those awards granted in 2004 rather than in 2005 and (b) expand the information contained in certain of the footnotes to the Summary Compensation Table.

This report continues to speak as of the date of the Original Filing, and we have not updated the disclosure in this report to speak as of a later date. All information contained in this report and the Original Filing is subject to updating and supplementing as provided in our periodic reports filed with the Securities and Exchange Commission.

i

PART III

The officers of the general partner manage and operate our business. We do not directly employ any of the persons responsible for managing or operating our business, but instead reimburse the general partner for the services of such persons. The following table sets forth the compensation paid during 2004, 2003 and 2002 for services rendered on behalf of the Partnership to the general partner’s Chief Executive Officer and the other four most highly compensated executive officers whose compensation exceeded $100,000 in 2004

Summary Compensation Table

Compensation of Directors

During the year ended December 31, 2004, each non-employee director of the general partner was entitled to receive 4,000 restricted units upon election to the Board, 1,000 common units on the first business day of each year and quarterly cash payments of $3,750 each. Each non-employee director also received $1,000 for each Board of Directors and committee meeting he attended. Committee Chairmen received an additional $250 for each meeting they chaired.

Beginning on January 1, 2005, each non-employee director of the general partner will receive an annual retainer of $110,000, consisting of $20,000 of cash and $90,000 worth of deferred common units. The actual number of deferred common units awarded in any given year will be based on the fair market value of the Partnership’s units on the date on which such award is granted. Each deferred common unit represents one common unit representing a limited partner interest in the Partnership, which vests immediately upon issuance and is available to the holder upon termination or retirement from the Board. The Chairperson of the Audit Committee receives an annual cash retainer of $15,000, and each Audit Committee member receives an annual cash retainer of $10,000. The Chairpersons of all other Committees receive annual cash retainers of $2,500. In addition to annual retainers, each non-employee director receives $1,000 cash for each Board of Directors and Committee meeting he attends. Directors appointed during a year, or who cease to be directors during a year, receive a pro rata portion of cash and deferred common units. Directors may elect to receive any cash payments in common stock or deferred common units, and may elect to defer the receipt of any cash or units they receive under the Company’s Non-Employee Directors Deferred Compensation Plan.

Long-term Incentive Plan

The Amended and Restated Penn Virginia Resource GP, LLC, Long-Term Incentive Plan permits the grant of awards covering an aggregate of 300,000 common units to employees and directors of the general partner and employees of its affiliates who perform services for us. Awards under the long-term incentive plan can be for common units, restricted units, unit options, phantom units and deferred common units. The plan is administered by the compensation committee of the general partner’s board of directors.

Our general partner’s board of directors in its discretion may terminate or amend the long-term incentive plan at any time with respect to any units for which a grant has not yet been made. The general partner’s board of directors also has the right to alter or amend the long-term incentive plan or any part of the plan from time to time, including increasing the number of units that may be granted subject to unitholder approval as required by the exchange upon which the common units are listed at that time. However, no change in any outstanding grant may be made that would materially impair the rights of the participant without the consent of the participant.

2

Restricted Units. A restricted unit entitles the grantee to receive a common unit upon the vesting of the restricted unit. The general partner granted 16,400 restricted units to directors, officers and employees of the general partner in 2004 with respect to services rendered in 2003. Restricted units vest upon terms established by the committee, but in no case earlier than the conversion to common units of the Partnership’s outstanding subordinated units. In addition, the restricted units will vest upon a change of control of the general partner or Penn Virginia Corporation.

If a grantee’s employment with or membership on the board of directors of the general partner terminates for any reason, the grantee’s restricted units will be automatically forfeited unless, and to the extent, the compensation committee provides otherwise. Common units to be delivered upon the vesting of restricted units may be common units acquired by the general partner in the open market, common units already owned by the general partner, common units acquired by the general partner directly from us or any other person or any combination of the foregoing. The general partner will be entitled to reimbursement by us for the cost incurred in acquiring common units.

Distributions payable with respect to restricted units may, at the committee’s request, be paid directly to the grantee or held by the Company and made subject to a risk of forfeiture during the applicable restriction period.

Unit Options. The long-term incentive plan also permits the grant of options covering common units. No grants of unit options have been made under the long-term incentive plan. Unit options will have an exercise price that, in the discretion of the committee, may be less than, equal to or more than the fair market value of the units on the date of grant. In general, unit options granted will become exercisable over a period determined by the compensation committee. In addition, the unit options will become exercisable upon a change in control of the general partner or Penn Virginia Corporation.

Upon exercise of a unit option, the general partner will acquire common units in the open market or directly from us or any other person or use common units already owned by the general partner, or any combination of the foregoing. The general partner will be entitled to reimbursement by us for the difference between the cost incurred by the general partner in acquiring these common units and the proceeds received by the general partner from an optionee at the time of exercise. Thus, the cost of the unit options will be borne by us.

Phantom Units. A phantom unit entitles the grantee to receive a common unit upon the vesting of the phantom unit, or in the discretion of the compensation committee, the cash equivalent of the value of a common unit. The compensation committee will determine the time period over which phantom units granted to employees and directors will vest. In addition, the phantom units will vest upon a change of control of the general partner or Penn Virginia Corporation.

If a grantee’s employment or membership on the board of directors terminates for any reason, the grantee’s phantom units will be automatically forfeited unless, and to the extent, the compensation committee provides otherwise. Common units delivered upon the vesting of restricted units may be common units acquired by the general partner in the open market, common units already owned by the general partner, common units acquired by the general partner directly from us of any other person or any combination of the foregoing. The general partner will be entitled to reimbursement by us for the cost incurred in acquiring common units. The compensation committee, in its discretion, may grant tandem distribution equivalent rights with respect to phantom units.

Deferred Common Units. The long-term incentive plan permits the grant of deferred common units to directors. Each deferred common unit represents one common unit, which vests immediately upon issuance and is available to the holder upon termination or retirement from the board of directors of the general partner. Deferred common units awarded to directors receive all cash or other distributions paid by the Partnership on account of its common units.

3

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

PENN VIRGINIA RESOURCE PARTNERS, L.P.

By: PENN VIRGINIA RESOURCE GP, LLC

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

4

Part IV

Item 15. Exhibits, Financial Statement Schedules and Reports on Form 8-K

The following documents are filed as exhibits to this Report on Form 10-K/A.

(a) Exhibits

5