Though written at some point after the battle, one of the greatest of all genuine Civil War songs is "The Battle of Shiloh's Hill." One text (with a midi) is at

       http://gordonfamilygenealogy.homestead.com/Shiloh.html

Another, rather different (also with a midi)is in the DT.

If you're of a literary turn, Herman melville, author of "Moby Dick," wrote a well-known poem called "Shiloh." It contains the memorable question, "What like a bullet can undeceive?"

http://eir.library.utoronto.ca/rpo/display/poem2854.html