Coffman Cove Administrative Site Conveyance Act of 2008 - Directs the Secretary of Agriculture to convey to the city of Coffman Cove, Alaska, without consideration and by quitclaim deed, a specified parcel of National Forest System land within the city. Excludes a certain part of such land from the conveyance. Allows the United States to reserve a right-of-way to provide access to the excluded land. Provides that if any part of the land conveyed to the city (other than a part of land sold pursuant to this Act) ceases to be used for public purposes, the land may revert to the United States. Requires, if the city sells any part of such conveyed land: (1) the amount of consideration for the sale to reflect fair market value, as determined by an appraisal; and (2) the city to pay to the Secretary an amount equal to the gross proceeds of the sale which shall be available for the Tongass National Forest.