http://civil-war-soldiers.findthedata.org/
Don't use the above URL and expect to find the site, rather enter the above address on google and it should take you there. I ran across it by accident a few days ago and thus far it has saved me hours of time on some soldiers and appears to be run in connection with the NPS. It has its good and bad points and used in combination with fold 3 it can be quite accurate.