Vincent Tume offers a Fire and Fury scenario generator program. I can’t test it, because I don’t own a macintosh. But I’d really like someone out there to give it a go and tell me what its like.
Rudi Geudens has written a modification of Richard Borg’s Battlecry game for miniatures. You need a set of the original rules to play, though.
North Against South is a set of free wargames rules for civil war battles. It’s based on the boardgame Battle Cry by Richard Borg.
Peter Hunt of the Hong Kong Society of Wargamers has written a set of articles about Naval Warfare in the American Civil War. This is, I think, a sadly neglected period for wargamers. I have a couple of dozen ships in 1/1200 scale, and the games have always been well received.