Military Valor Roll of Honor Act of 2008 - Directs the Secretary of Defense to establish the Military Valor Roll of Honor registry which shall: (1) contain the names and citations of all members of the Armed Forces, members of the U.S. merchant marine (including the Army Transport Service and the Naval Transport Service), and civilians affiliated with the Armed Forces who have been awarded the medal of honor or any other medal authorized by Congress for the Armed Forces, the U.S. merchant marine, or affiliated civilians; and (2) be a publicly available database.