Here's the url for a great site on civil war music.

http://www.civilwarmidi.homepage.com/

Also, there was a thread about a month ago on "Derek Warfields 'Sons of Erin' ", in re his CD by that title which is entirely Civil War songs (with an accompanying 32 page booklet) and a separately published book of his with lyrics and extensive notes for 49 civil war songs. Great stuff.