Government Real Estate Accountability and Transparency Act of 2008 - Requires the submission of annual reports: (1) describing the total quantity of land within the jurisdiction of the United States, the land that is owned by the federal government, and the land that is located within each state; (2) describing the total annual cost to the government for maintaining all parcels of administrative land and all administrative buildings or structures under the jurisdiction of each federal agency; and (3) listing and summarizing the unused or vacant assets of each agency and the estimated costs to the government of the maintenance backlog of each agency.