Outer Continental Shelf Leasing Amendments Act - Amends the Outer Continental Shelf Lands Act to require the Secretary of Energy and the Governor of a coastal State to notify each other and enter into a unitization agreement for Federal and State leases whenever they determine a common hydrocarbon-bearing area exists. Requires disagreements as to the existence or the unitization of such area to be submitted to arbitration. Requires the Secretary and the Governor to establish a unit of such area consistent with the arbitration. Sets forth requirements for the administration of such unit, including the allocation of hydrocarbons.