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                                                                   EXHIBIT 10.56

              COST AND EXPENSE SHARING AND REIMBURSEMENT AGREEMENT

         THIS COST AND EXPENSE SHARING AND REIMBURSEMENT AGREEMENT (this
"AGREEMENT") is effective as of the 21st day of March, 2001, by and between
PINNACLE TOWERS INC., a Delaware corporation ("PTI") and Pinnacle Towers V Inc.,
a Florida corporation ("PT5").

         WHEREAS, PT5 on its own behalf and through its wholly owned
subsidiaries, Shaffer and Associates, Inc. and Sierra Towers, Inc. (each a
"Subsidiary" and collectively, the "Subsidiaries"), is engaged in the rental and
management of communications sites; and

         WHEREAS, PT5 considers it necessary or convenient to utilize certain of
PTI's personnel, facilities and general and administrative overhead in
connection with its business and that of its Subsidiaries, and PTI is willing to
make such available to PT5 and its Subsidiaries; and

         WHEREAS, PT5 has agreed to reimburse PTI for the allocable share of the
cost and expense of such shared personnel, facilities and general and
administrative overhead as determined in the manner hereinafter provided;

         NOW, THEREFORE, in consideration of the representations, warranties,
covenants and agreements herein contained, the parties agree as follows:

         1. PROVISION OF SHARED COSTS AND EXPENSES. During the term of this
Agreement, upon the reasonable request of PT5 or a Subsidiary, PTI will make
available to PT5 and such Subsidiary any of PTI's office and administrative
personnel and facilities, consultants and contractors, and general and
administrative office overhead and costs, including inter alia office space,
record retention, photocopy facilities, facsimile and telephone equipment, sales
and marketing support, office supplies, and computer services (collectively, the
"SHARED COSTS AND EXPENSES").

         2. REIMBURSEMENT. PT5 agrees to reimburse PTI for the costs and
expenses incurred by PTI on behalf of or for the benefit of PT5 and its
Subsidiaries, in an amount equal to the sum of the following amounts (the
"REIMBURSEMENT AMOUNT") determined annually as of the end of each calendar year:

                  (a) With respect to any Shared Costs and Expenses directly
         attributable solely to PT5 or a Subsidiary, an amount equal to the
         marginal or incremental cost or expense thereof incurred by PTI; and

                  (b) With respect to any Shared Costs and Expenses not
         described in (a) above, the pro rata share of such Shared Costs and
         Expenses based on the product obtained by multiplying the gross amount
         of such Shared Costs and Expenses by the quotient obtained by dividing
         the consolidated gross revenues of PT5 and its Subsidiaries for the
         year by the sum of the consolidated gross revenues for the year of all
         of PTI, PT5, and the Subsidiaries, or an amount determined on such
         other reasonable basis as the parties may mutually agree.


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The Reimbursement Amount for each calendar year shall be determined no later
than three months after the end of such calendar year and payment of the
Reimbursement Amount shall be due on or before the April 10th of the year
following the end of such calendar year.

         3. STANDARD OF CARE. PTI agrees that it and its personnel shall
exercise the same degree of diligence, care and prudence in connection with
matters conducted on behalf of, or provided for the benefit of, PT5 or its
Subsidiaries as it exercises matters conducted on its own behalf or provided for
its own benefit.

         4. LIMITATION OF LIABILITY.

                  (a) PTI and its affiliates, and the officers, directors,
         employees, shareholders, partners, representatives, consultants and
         agents of PTI and its affiliates (collectively, "PROVIDING PARTIES")
         shall not be liable to the party on whose behalf the Shared Costs and
         Expenses are incurred, its affiliates, or to any officer, director,
         employee, shareholder, partner, representative, consultant or agent of
         such party or its affiliates (collectively, "RECEIVING PARTIES"), for
         any liability, cost, damage, expense or loss, including, without
         limitation, any special, indirect, consequential or punitive damages
         (i) arising or allegedly arising out of any actions or failures to act
         by any of the Providing Parties with respect to the Shared Costs and
         Expenses to be provided hereunder, or (ii) as a result of the reliance
         by any of the Receiving Parties on any advice or data that any of the
         Providing Parties may provide pursuant to this Agreement; provided,
         however, that the foregoing shall not apply to limit liability of a
         party to the extent caused by such party's gross negligence or willful
         misconduct.

                  (b) The Receiving Parties shall indemnify and hold harmless
         each and every of the Providing Parties from and against any liability,
         cost, damage, expense or loss (including court costs and reasonable
         attorneys' fees) which such Providing Parties may sustain or incur by
         reason of any claim, demand, suit or recovery by any person or entity,
         directly resulting from acts or omissions committed by the Receiving
         Party in connection with this Agreement; provided, however, that no
         person may benefit from the foregoing indemnity in the event of its
         gross negligence or willful misconduct.

         5. TERM. The term of this Agreement shall commence as of the date
hereof and end December 31, 2001, unless earlier terminated effective as of the
end of a calendar month by either party upon no less than two months' prior
written notice to the other party. The term of this Agreement shall
automatically renew for successive periods of one year each unless either party
provides to the other party notice in writing that this Agreement will not so
renew and such notice is given at least two months prior to the then termination
date of this Agreement. In the event this Agreement is terminated prior to the
end of a calendar year, the Reimbursement Amount shall be determined as of the
effective date of termination based on gross revenues of each party through the
date of termination.

         6. RELATIONSHIP OF THE PARTIES. In all matters relating to this
Agreement, each party hereto shall be solely responsible for the acts of its
employees, and employees of one party shall not be considered employees of the
other party. No party shall have any right, power or authority to create any
obligation, express or implied, on behalf of any other party. Nothing in


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this Agreement is intended to create or constitute a joint venture or
partnership relationship between the parties hereto or persons referred to
herein.

         7. FORCE MAJEURE. PTI shall be excused from performance hereunder for
any period and to the extent that it is prevented from performance hereunder, in
whole or in part, as a result of delays caused by PT5 or its Subsidiaries or any
act of God, war, civil disturbance, court order, strike, labor dispute, law or
regulation of any governmental authority, or other cause beyond the reasonable
control of PTI. Such nonperformance shall not be a default hereunder. PTI shall
take all reasonable actions to resume performance of its obligations hereunder
as soon as feasible.

         8. AMENDMENTS AND WAIVER. No amendment, waiver or consent with respect
to any provision of this Agreement shall in any event be effective, unless the
same shall be in writing and signed by the parties hereto, and then such
amendment, waiver or consent shall be effective only in the specific instance
and for the specific purpose for which given.

         9. NOTICES. All notices, requests, demands and other communications
hereunder shall be in writing and shall be, personally delivered or sent by
facsimile transmission with confirming copy sent by overnight courier (such as
Express Mail, Federal Express, etc.) and a delivery receipt obtained and
addressed to the intended recipient as follows:

                  If to PTI:

                           Pinnacle Towers Inc.
                           301 North Cattlemen Road, Suite 300
                           Sarasota, FL 34232
                           Attention: Ben Gaboury
                           Telephone No.: (941) 364-8886
                           Facsimile No.: (941) 364-8761

                  If to PT5:

                           Pinnacle Towers V Inc.
                           301 North Cattlemen Road, Suite 300
                           Sarasota, FL 34232
                           Attention: Steve Day
                           Telephone No.: (941) 364-8886
                           Facsimile No.: (941) 364-8761

Any party may change its address or add or change parties for receiving notice
by written notice given to the others named above. Notices shall be deemed given
as of the date of receipt.

         10. COUNTERPARTS. This Agreement may be executed in counterparts, each
of which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

         11. SUCCESSORS AND ASSIGNS; BENEFICIARIES. This Agreement shall bind
and inure to the benefit of the parties named herein and their respective
successors and assigns. No party may assign any rights, benefits, duties or
obligations under this Agreement without the prior written consent of the other
party. Except for the Subsidiaries each of which is an intended beneficiary


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of this Agreement, and except as specifically provided in Section 4, no third
party shall be entitled to enforce any provision hereof or to benefit from this
Agreement.

         12. ENTIRE AGREEMENT. This Agreement and the documents referred to
herein contain the entire agreement and understanding among the parties with
respect to the transactions contemplated hereby and supersede all other
agreements, understandings and undertakings among the parties on the subject
matter hereof.

         13. PARTIAL INVALIDITY. In the event that any provision of this
Agreement shall be held invalid or unenforceable by any court or competent
jurisdiction, such holding shall not invalidate or render unenforceable any
other provision hereof.

         14. GOVERNING LAW; JURISDICTION. This Agreement shall be interpreted in
accordance with the substantive laws of the State of Florida applicable to
contracts made and to be performed wholly within said State. All disputes, legal
actions, suits and proceedings arising out of or relating to this Agreement
shall be brought in a federal district or state court located in Tampa, Florida.
Each party hereby consents to the jurisdiction of the federal district or state
court in Tampa, Florida. Each party hereby irrevocably waives all claims of
immunity from jurisdiction and any right to object on the basis that any
dispute, action, suit or proceeding brought in the federal district or state
court of Tampa, Florida has been brought in an improper or inconvenient venue or
forum.

         15. DISPUTES.

                  (a) PTI and PT5 mutually desire that friendly collaboration
         will develop between themselves. Accordingly, they shall attempt to
         resolve in a friendly manner all disagreements and misunderstandings
         connected with their respective rights and obligations under this
         Agreement, including any amendments hereof.

                  (b)      (i) To the extent that any misunderstanding or
         dispute cannot be resolved agreeably in a friendly manner, the dispute
         will be mediated by a mutually acceptable mediator to be chosen by PTI
         and PT5 within forty-five (45) days after written notice by one of the
         parties demanding mediation. Neither party may unreasonably withhold
         consent to the selection of a mediator, however, by mutual agreement
         PTI and PT5 may postpone mediation until each has completed specified
         but limited discovery with respect to a dispute. The parties may also
         agree to attempt some other form of alternative dispute resolution
         ("ADR") in lieu of mediation, including by way of example and without
         limitation, neutral fact-finding or a mini-trial.

                           (ii) Any dispute which the parties cannot resolve
         through negotiation, mediation or other form of ADR within six months
         of the date of the initial demand for it by one of the parties may then
         be submitted to the courts for resolution. The use of any ADR
         procedures will not be construed under the doctrine of laches, waiver
         or estoppel to affect adversely the rights of either party. Nothing in
         this Section 15 will prevent any party from resorting to judicial
         proceedings if (A) good faith efforts to resolve the dispute under
         these procedures have been unsuccessful or (B) interim relief from a
         court is necessary to prevent serious and irreparable injury to one
         party or to others.


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                  (c) Each of the parties shall bear its own costs of mediation
         or ADR, but the parties agree that the shared costs of mediation or ADR
         shall be shared 50% by PTI and 50% by PT5.

         16. AUTHORSHIP. The parties hereto agree that the terms and language of
this Agreement were the result of negotiations between the parties and, as a
result, there shall be no presumption that any ambiguities in this Agreement
shall be resolved against either party. Any controversy over construction of
this Agreement shall be decided without regard to events of authorship or
negotiation.

         17. DEFINED TERMS. All capitalized terms not defined herein shall have
the meanings ascribed to them in the Asset Purchase Agreement.

         18. RECITALS. The recitals hereto are true and correct and are by this
reference incorporated herein.

         IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the date first above written.

PINNACLE TOWERS INC.                         PINNACLE TOWERS V INC.


By:                                          By:
   --------------------------------             --------------------------------
   Name:                                        Name:
        ---------------------------                  ---------------------------
   Title:                                       Title:
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