<PAGE>   1
                                                                  Exhibit 10.71

                                                                  EXECUTION COPY

                              AMENDMENT AND CONSENT


            AMENDMENT AND CONSENT, dated as of June 18, 1998 (this "Amendment
and Consent"), to the Fifth Amended and Restated Credit Agreement, dated as of
August 15, 1997 (as amended, supplemented or otherwise modified from time to
time, the "Credit Agreement"), among OUTDOOR SYSTEMS, INC. (the "Company"),
MEDIACOM, INC. (the "Canadian Borrower"; together with the Company, the
"Borrowers"), the several banks and other financial institutions from time to
time parties thereto (the "Lenders"), CANADIAN IMPERIAL BANK OF COMMERCE, as
Canadian Administrative Agent, and CANADIAN IMPERIAL BANK OF COMMERCE, NEW YORK
AGENCY, as US Administrative Agent (in such capacity, the "US Administrative
Agent"; together with the Canadian Administrative Agent, the "Agents").



                              W I T N E S S E T H:


            WHEREAS, the Borrowers, the Lenders and the Agents are parties to
the Credit Agreement;

            WHEREAS, the Borrowers have requested that the Lenders agree to
amend certain provisions of the Credit Agreement, and the Lenders are agreeable
to such request upon the terms and subject to the conditions set forth herein;

            NOW, THEREFORE, in consideration of the premises and mutual
agreements contained herein, and for other valuable consideration the receipt of
which is hereby acknowledged, the Borrowers, the Lenders and the Agents hereby
agree as follows:


            1 Definitions. All terms defined in the Credit Agreement shall have
such defined meanings when used herein unless otherwise defined herein.

            2 Amendment of Subsection 2.4(a). Subsection 2.4(a) of the Credit
Agreement is hereby amended by replacing it with the following new subsection
2.4(a):

                  "2.4 Increase of Revolving Credit Commitments. (a) The Company
      may from time to time, by notice to the US Administrative Agent, request
      that the US Revolving Credit Commitments and/or the Canadian Revolving
      Credit Commitments be increased on or prior to December 31, 1999 by
<PAGE>   2
                                                                             2

     an amount that is not less than US$25,000,000 or C$25,000,000, as the case
     may be, and will not result in the aggregate amount of the US Revolving
     Credit Commitments and the Canadian Revolving Credit Commitments exceeding
     US$700,000,000, provided that the aggregate amount of the Canadian
     Revolving Credit Commitments and principal amount of all Canadian Term
     Loans outstanding after giving effect thereto may not exceed C$250,000,000
     unless the applicable Canadian Security Documents have been amended in a
     manner reasonably satisfactory to the Canadian Administrative Agent to
     reflect such greater amount. (For purposes of calculations pursuant to this
     subsection all amounts denominated in Canadian Dollars shall be converted
     to US Dollars at the US$ Equivalent amount thereof.) Upon receipt of such
     notice the US Administrative Agent shall seek to obtain the agreement of
     one or more of the US Revolving Credit Lenders and/or Canadian Revolving
     Credit Lenders to increase its or their US Revolving Credit Commitments
     and/or, as the case may be, Canadian Revolving Credit Commitments by an
     aggregate amount equal to the increase so requested by the Company."

            3 Consent. The Lenders hereby consent and agree that, in any
calculation of the Senior Leverage Ratio or the Total Leverage Ratio made as
of December 31, 1998 or any date prior to December 31, 1998, the Company shall
be entitled to deduct (a) the then dollar equivalent of the aggregate then
unrefunded amount of value-added tax paid by the Company and/or its Restricted
Subsidiaries in connection with the acquisitions of Vendor S.A. de C.B. and the
outdoor advertising assets of Multimedios Estrellas de Oro, S.A. de C.B. and MM
Billboard, S.A. de C.B. from (b) the amount of the then outstanding
Indebtedness.

            4 Conditions to Effectiveness. This Amendment and Consent shall
become effective on and as of the date that the US Administrative Agent shall
have received counterparts of this Amendment and Consent, duly executed and
delivered by a duly authorized officer of each of the Borrowers, and the
Majority Lenders and consented to by each Guarantor.

            5 Limited Amendment. Except as expressly amended herein, the Credit
Agreement shall continue to be, and shall remain, in full force and effect. This
Amendment and Consent shall not be deemed to be a waiver of, or consent to, or
a modification or amendment of, any other term or condition of the Credit
Agreement (including, without limitation, the financial covenants set forth in
subsection 8.1) or any other Loan Document or to prejudice any other right or
rights which the Lenders may now have or may have in the future under or in
connection with the Credit Agreement or any of the instruments or agreements
referred to therein, as the same may be amended from time to time.

            6 Counterparts. This Amendment and Consent may be executed by one
or more of the parties hereto in any number of separate counterparts, and all of
said counterparts taken together shall be deemed to constitute one and the same
instrument.

            7 GOVERNING LAW. THIS AMENDMENT AND CONSENT SHALL BE GOVERNED BY,
AND CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF
NEW YORK.
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                                                                               4

            IN WITNESS WHEREOF, the parties hereto have caused this Amendment
and Consent to be executed and delivered by their respective duly authorized
officers as of the date first above written.

                                    OUTDOOR SYSTEMS, INC.


                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    MEDIACOM, INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:

                                    CANADIAN IMPERIAL BANK OF
                                    COMMERCE, as Canadian Administrative Agent
                                    and as a Lender

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    CIBC INC., as a Lender

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    CANADIAN IMPERIAL BANK OF COMMERCE, NEW YORK
                                    AGENCY, as US Administrative Agent and as a
                                    Lender

                                    By: /s/
                                        -----------------------------------
                                        Title:
<PAGE>   4
                                    ALLSTATE INSURANCE COMPANY

                                    By: /s/
                                        -----------------------------------
                                        Title:

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    ALLSTATE LIFE INSURANCE COMPANY

                                    By: /s/
                                        -----------------------------------
                                        Title:

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    BANK OF AMERICA NATIONAL TRUST &
                                    SAVINGS ASSOCIATION

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    BANK OF AMERICA CANADA

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    BANK OF HAWAII

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    THE BANK OF MONTREAL, CHICAGO BRANCH

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    THE BANK OF NEW YORK

                                    By: /s/
                                        -----------------------------------
                                        Title:
<PAGE>   5
                                    THE BANK OF NOVA SCOTIA

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    THE BANK OF NOVA SCOTIA - CANADA

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    BANKBOSTON, N.A.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    BANQUE NATIONALE DE PARIS

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    BANQUE PARIBAS

                                    By: /s/
                                        -----------------------------------
                                        Title:

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    BANK ONE, ARIZONA, NA

                                    By: /s/
                                        -----------------------------------
                                        Title:
<PAGE>   6
                                    BAYERISCHE VEREINSBANK A.G.

                                    By: /s/
                                        -----------------------------------
                                        Title:

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    CARILLON HOLDING, LTD.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    CITY NATIONAL BANK

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    COMPAGNIE FINANCIERE DE CIC ET DE
                                    L'UNION EUROPEENNE

                                    By: /s/
                                        -----------------------------------
                                        Title:

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    CONTINENTAL ASSURANCE COMPANY
                                    SEPARATE ACCOUNT (E)
                                    BY: TCW ASSET MANAGEMENT COMPANY
                                    AS ATTORNEY-IN-FACT

                                    By: /s/
                                        -----------------------------------
                                        Title:

                                    By: /s/
                                        -----------------------------------
                                        Title:
<PAGE>   7
                                    CORESTATES BANK, N.A.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    CREDIT LYONNAIS, LOS ANGELES BRANCH

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    CREDIT LYONNAIS CANADA

                                    By: /s/
                                        -----------------------------------
                                        Title:

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    CREDITANSTALT CORPORATE FINANCE, INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    CRESCENT/MACH I PARTNERS, L.P.
                                    BY: TCW ASSET MANAGEMENT, ITS
                                    INVESTMENT MANAGER

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    DEEPROCK & COMPANY

                                    By: /s/
                                        -----------------------------------
                                        Title:
<PAGE>   8
                                    DLJ CAPTIAL FUNDING, INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    DRESDNER BANK AG NEW YORK & GRAND
                                    CAYMAN BRANCHES

                                    By: /s/
                                        -----------------------------------
                                        Title:

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    DRESDNER BANK CANADA

                                    By: /s/
                                        -----------------------------------
                                        Title:

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    FIRST HAWAIIAN BANK

                                    By: /s/
                                        -----------------------------------
                                        Title:
<PAGE>   9
                                    FIRST NATIONAL BANK OF MARYLAND

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    FIRST UNION NATIONAL BANK (f/k/a FIRST
                                    UNION BANK OF NORTH CAROLINA

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    FLEET NATIONAL BANK

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    THE FUJI BANK LIMITED, LOS ANGELES AGENCY

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    GENERAL ELECTRIC CAPITAL CORPORATION

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    IMPERIAL BANK, A CALIFORNIA BANKING
                                    CORPORATION

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    INDOSUEZ CAPITAL FUNDING II, LIMITED
                                    BY: INDOSUEZ CAPITAL, AS PORTFOLIO ADVISOR

                                    By: /s/
                                        -----------------------------------
                                        Title:
<PAGE>   10
                                    INDUSTRIAL BANK OF JAPAN, LTD., LOS ANGELES
                                    AGENCY

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    INDUSTRIAL BANK OF JAPAN LTD., NEW YORK
                                    AGENCY

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    KZH-CRESCENT CORPORATION

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    KZH-SOLEIL CORPORATION

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    THE LONG TERM CREDIT BANK OF JAPAN, LTD.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    MASSACHUSETTS MUTUAL LIFE INSURANCE COMPANY

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    MELLON BANK, N.A.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    MELLON BANK CANADA
<PAGE>   11
                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    MERITA BANK LTD. - NEW YORK BRANCH

                                    By: /s/
                                        -----------------------------------
                                        Title:

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    MERRILL LYNCH PRIME RATE PORTFOLIO
                                    BY: MERRILL LYNCH ASSET MANAGEMENT,
                                    L.P., AS INVESTMENT ADVISOR

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    MERRILL LYNCH SENIOR FLOATING RATE FUND,
                                    INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    METROPOLITAN LIFE INSURANCE COMPANY

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    MICHIGAN NATIONAL BANK

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    THE MITSUBISHI TRUST AND BANKING
                                    CORPORATION, LOS ANGELES AGENCY

                                    By: /s/
                                        -----------------------------------
                                        Title:
<PAGE>   12
                                    NATIONAL CITY BANK

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    NORWEST BANK ARIZONA, N.A.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    PARIBAS BANK OF CANADA

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    PARIBAS CAPITAL FUNDING L.L.C.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    ROYALTON COMPANY

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    SANWA BANK LTD.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    SENIOR DEBT PORTFOLIO

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    SOUTHERN PACIFIC BANK

                                    By: /s/
                                        -----------------------------------
                                        Title:
<PAGE>   13
                                    THE SUMITOMO BANK, LIMITED, NEW YORK BRANCH

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    THE SUMITOMO BANK OF CANADA

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    SUMITOMO TRUST & BANKING CO., LTD.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    TORONTO DOMINION (TEXAS), INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    THE TRAVELERS INSURANCE COMPANY

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    UNION BANK OF CALIFORNIA NA

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    VAN KAMPEN AMERICAN CAPITAL PRIME RATE
                                    INCOME TRUST

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    VAN KAMPEN CLO1, LIMITED
<PAGE>   14
                                    BY: VAN KAMPEN AMERICAN CAPITAL MANAGEMENT,
                                    INC., AS COLLATERAL MANAGER

                                    By: /s/
                                        -----------------------------------
                                        Title:
<PAGE>   15
The undersigned hereby consent and agree to the foregoing Amendment and Consent.


                                    OUTDOOR SYSTEMS PAINTING, INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    OS ADVERTISING OF TEXAS
                                     PAINTING, INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    OS BASELINE, INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    DECADE COMMUNICATIONS GROUP, INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    BENCH ADVERTISING COMPANY OF
                                    COLORADO, INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    NEW YORK SUBWAYS ADVERTISING CO., INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:
<PAGE>   16
                                    OUTDOOR SYSTEMS, INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    OUTDOOR SYSTEMS (NEW YORK), INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    OS BUS, INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    NATIONAL ADVERTISING COMPANY

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    PACIFIC CONNECTION, INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    SALM ENTERPRISES, INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:


                                    ATLANTIC PROSPECT, INC.

                                    By: /s/
                                        -----------------------------------
                                        Title:

                                    OS, FLORIDA, INC.

                                    By: /s/
                                        -----------------------------------
                                        Title: