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                                                                    EXHIBIT 4.41

                             SUPPLEMENTAL INDENTURE

                                       OF

                                   GUARANTORS

         THIS SUPPLEMENTAL INDENTURE dated as of December 31, 2000 is delivered
pursuant to Section 10.04 of the Indenture dated as of November 15, 1996 (as
heretofore or hereafter modified and supplemented and in effect from time to
time, the "Indenture") among LAMAR MEDIA CORP., a Delaware corporation,
(formerly Lamar Advertising Company) certain of its subsidiaries ("Guarantors")
and STATE STREET BANK AND TRUST COMPANY, a Massachusetts banking corporation, as
Trustee ("Trustee") (all terms used herein without definition having the
meanings ascribed to them in the Indenture).

         The undersigned hereby agree that:

         1. The undersigned is a Guarantor under the Indenture with all of the
rights and obligations of a Guarantor thereunder.

         2. The undersigned hereby grants, ratifies and confirms the guarantee
provided for by Article Ten of the Indenture to guarantee unconditionally,
jointly and severally with the other Guarantors, to each Holder of a Note
authenticated and delivered by the Trustee, and to the Trustee on behalf of such
Holder, the due and punctual payment of the principal of (and premium, if any)
and interest on such Note when and as the same shall become due and payable.

         3. The undersigned hereby represents and warrants that the
representations and warranties set forth in the Indenture, to the extent
relating to the undersigned as Guarantor, are correct on and as of the date
hereof.

         4. All notices, requests and other communications provided for in the
Indenture should be delivered to the undersigned at the address specified in
Section 12.02 of the Indenture.

         5. A counterpart of this Supplemental Indenture may be attached to any
counterpart of the Indenture.

         6. This Supplemental Indenture shall be governed by and construed in
accordance with the laws of the State of New York.

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         IN WITNESS WHEREOF, the undersigned have caused this Supplemental
Indenture to be duly executed as of the day and year first above written.

                                   Guarantor:

                                   TEXAS LOGOS, L.P.
                                   a Texas Limited Partnership

                                   By: Oklahoma Logos, L.L.C.
                                   Its: General partner

                                   By: Interstate Logos, L.L.C.
                                   Its: Managing member

                                   By: Lamar Media Corp.,
                                   Its: Managing member

                                   By:  /s/ Keith A. Istre
                                      -----------------------------------------
                                        Keith A. Istre
                                        Vice President - Finance and
                                        Chief Financial Officer
Attest:

By:      /s/ James R. McIlwain
   ----------------------------------
     James R. McIlwain, Secretary

Accepted:

STATE STREET BANK AND TRUST
         COMPANY, as Trustee

By:      /s/ Andrew L. Sciorz
   ----------------------------------

Title:   Assistant Vice President
      -------------------------------

                                       2<PAGE>   1
                                                                    EXHIBIT 4.42

                             SUPPLEMENTAL INDENTURE

                       TO INDENTURE DATED AUGUST 15, 1997

         THIS SUPPLEMENTAL INDENTURE dated as of December 31, 2000, is delivered
pursuant to Section 4.11 of the Indenture dated as of August 15, 1997 (as
heretofore or hereafter modified and supplemented and in effect from time to
time, the "1997 Indenture") among OUTDOOR COMMUNICATIONS, INC., a Delaware
corporation, certain of its subsidiaries (the "Guarantors") and FIRST UNION
NATIONAL BANK, a national banking corporation, as Trustee (the "Trustee") (all
terms used herein without definition having the meanings ascribed to them in the
1997 Indenture).

         The undersigned hereby agrees that:

         1. The undersigned is a Guarantor under the 1997 Indenture with all of
the rights and obligations of the Guarantors thereunder.

         2. The undersigned has granted, ratified and confirmed, in the form and
substance of Exhibit B to the 1997 Indenture, the Guarantee provided for by
Article XI of the 1997 Indenture.

         3. The undersigned hereby represents and warrants that the
representations and warranties set forth in the 1997 Indenture, to the extent
relating to the undersigned as Guarantor, are correct on and as of the date
hereof.

         4. All notices, requests and other communications provided for in the
1997 Indenture should be delivered to the undersigned at the following address:

            Keith A. Istre
            Vice President - Finance and
            Chief Financial Officer
            Lamar Media Corp. and its Subsidiaries
            5551 Corporate Blvd.
            Baton Rouge, LA 70808

         5. A counterpart of this Supplemental Indenture may be attached to any
counterpart of the 1997 Indenture.

         6. This Supplemental Indenture shall be governed by and construed in
accordance with the internal laws of the State of New York.

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         IN WITNESS WHEREOF, the undersigned have caused this Supplemental
Indenture to be duly executed as of the day and year first above written.

                                   Guarantor:

                                   TEXAS LOGOS, L.P.
                                   a Texas Limited Partnership

                                   By: Oklahoma Logos, L.L.C.
                                   Its: General partner

                                   By: Interstate Logos, L.L.C.
                                   Its: Managing member

                                   By: Lamar Media Corp.,
                                   Its: Managing member

                                   By:  /s/ Keith A. Istre
                                      ----------------------------------------
                                        Keith A. Istre
                                        Vice President - Finance and
                                        Chief Financial Officer

Attest:

By:      /s/ James R. McIlwain
   -------------------------------------
     James R. McIlwain, Secretary

Accepted:

FIRST UNION NATIONAL BANK, as Trustee

By:  /s/ James Long
   -------------------------------------
Title:   Assistant Vice President
      ----------------------------------

                                       2<PAGE>   1
                                                                   EXHIBIT 10.27
                                                                [Execution copy]

                       AMENDMENT NO. 1 TO CREDIT AGREEMENT
                        AND GUARANTY AND PLEDGE AGREEMENT

               AMENDMENT NO. 1 TO CREDIT AGREEMENT AND GUARANTY AND PLEDGE
AGREEMENT dated as of April 10, 2000 in respect of (i) the Credit Agreement
dated as of August 13, 1999 (the "Credit Agreement") between Lamar Media Corp.
(the "Borrower"), the Subsidiary Guarantors party thereto, the lenders party
thereto, and The Chase Manhattan Bank, as Administrative Agent (in such
capacity, the "Administrative Agent"), and (ii) the Guaranty and Pledge
Agreement dated as of September 15, 1999 (the "Holdings Guaranty and Pledge
Agreement") between Lamar Advertising Company ("Holdings") and the
Administrative Agent.

               The Borrower and Holdings have requested that the Administrative
Agent consent to certain amendments to the Credit Agreement and the Holdings
Guaranty and Pledge Agreement. The Administrative Agent, pursuant to authority
granted by, and having obtained all necessary consents of, the Required Lenders
(as defined in the Credit Agreement), has agreed to such amendments and,
accordingly, the parties hereto hereby agree as follows:

               Section 1. Definitions. Terms defined in the Credit Agreement and
used herein are used herein as defined therein.

               Section 2. Amendment. Subject to the execution and delivery
hereof by the Borrower, Holdings, the Subsidiary Guarantors and the
Administrative Agent, but effective as of the date hereof, the Credit Agreement,
and the Holdings Guaranty and Pledge Agreement shall be amended as follows:

               2.01. General. References in the Credit Agreement and the
Holdings Guaranty and Pledge Agreement, respectively (including references to
the Credit Agreement and the Holdings Guaranty and Pledge Agreement as amended
hereby) to "this Agreement" (and indirect references such as "hereunder",
"hereby", "herein" and "hereof") shall be deemed to be references to the Credit
Agreement and the Holdings Guaranty and Pledge Agreement, respectively, as
amended hereby.

               2.02. Amendment to Credit Agreement. Clause (v) of Section
7.05(a) of the Credit Agreement is hereby amended in its entirety to read as
follows:

               "(v) Investments consisting of (x) loans made by the Borrower
         to any Special Acquisition Subsidiary (as defined in the Holdings
         Guaranty and Pledge Agreement), so long as (A) such loan is made to
         such Special Acquisition Subsidiary to enable the repayment of
         Indebtedness assumed in connection with the acquisition referred to in
         clause (b) of Article V of the Holdings Guaranty and Pledge Agreement,
         (B) no such loan shall be outstanding for a period of more than five
         Business Days unless, prior to the exploration of such period, such
         Special Acquisition Subsidiary shall have been contributed to the
         Borrower and become a Wholly Owned Subsidiary of the Borrower and (C)
         the aggregate principal amount of all such loans outstanding at any one
         time to

                                 Amendment No. 1

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                                      -2-

         all Special Acquisition Subsidiaries shall not exceed $100,000,000 and
         (y) other Investments in Affiliates not exceeding $15,000,000 at any
         one time outstanding."

               2.03. Amendment to Holdings Guaranty and Pledge Agreement.
Clauses (b) and (e) of Article V of the Holdings Guaranty and Pledge Agreement
shall be amended in their entirety to read as follows:

               "(b) acquire any property, other than Investments in equity
         securities in the Borrower and cash and cash equivalents, and other
         than Investments in Special Acquisition Subsidiaries and, for purposes
         hereof, "Special Acquisition Subsidiaries" shall mean any entity formed
         by Holdings that is a Wholly Owned Subsidiary of Holdings but not a
         Subsidiary of the Borrower, and that is formed for the sole purpose of
         affecting a tax free acquisition of another corporation (the "Target")
         under Section 368(a)(1)(A) and 368(a)(2)(E) of the Code, in which
         Holdings invests not more than $1,000 in cash at any one time and which
         Wholly Owned Subsidiary is contributed to the Borrower (and, thereby
         becomes a Wholly Owned Subsidiary of the Borrower) within five Business
         Days after the consummation of the merger or other transactions
         resulting in the acquisition of the Target;

               (c) engage in any business or other activity other than the
         business of holding the shares of capital stock of the Borrower and
         (subject to the conditions set forth in clause (b) above, Special
         Acquisition Subsidiaries) and activities relating to Qualified Holdings
         Obligations, or"

               Section 3. Miscellaneous. Except as expressly herein provided,
the Credit Agreement and the Holdings Guaranty and Pledge Agreement shall remain
unchanged and in full force and affect. This Amendment No. 1 may be executed in
any number of counterparts, all of which taken together shall constitute one and
the same amendatory instrument and any of the parties hereto may execute this
Amendment No. 1 by signing any such counterpart. This Amendment No. 1 shall be
governed by, and construed in accordance with, the law of the State of New York.

               IN WITNESS WHEREOF, the parties hereto have caused this amendment
No. 1 to be duly executed as of the day and year first above written.

                              BORROWER AND HOLDINGS

LAMAR MEDIA CORP.                     LAMAR ADVERTISING COMPANY

By     /s/ Keith A. Istre             By   /s/ Keith A. Istre
  -----------------------------         -----------------------------------
  Title:                                Title:

                                 Amendment No. 1

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