There are a couple of sources for Civil War enlistment and discharge records. At the state level the Indiana State Archives has the Index to the Muster Rolls that would contain this information. Information for ordering records from them can be found at http://www.in.gov/icpr/2804.htm

At the national level enlistment and discharge records can be ordered from the National Archives. Information for ordering these records can be found under Part 3: at http://www.archives.gov/genealogy/military/civil-war/index.html

Tony