The National Park Service in the U.S. has this free service compiled from service records and other resources. It's a a computerized database containing very basic facts about servicemen who served on both sides during the Civil War. This project began with the Names Index Project, a project to enter names and other basic information from 6.3 million soldier records in the National Archives. This site also includes information from regimental histories (Union and Confederate)and links to descriptions of 384 significant battles of the war. In time the system is expected to expand to include information about soldiers, sailors, regiments, and battles, as well as prisoner-of-war records and cemetery records.