There is a downloadable version of an old American Civil Wargame made available on the net by its developer - it was called something innovative like American Civil War and I have a vague memory it was by Frank Hunter, but I may be wrong - I downloaded it but never played it. It was strategic level and a pretty serious wargame, although graphically not up to Sid Meier or Total War.

At the tactical level, what I played a LOT was Norm Koger's Age of Rifles. This covered 1816-1905 or there abouts, but naturally had many Civil War scenarios. It was a good fun, hex and turn based wargame with a solid historical database, a decent IGO-UGO game system and reasonable AI - in many ways comparable to Steel Panthers. I believe it is available to download from the Home of the Underdogs - the company selling it (SSI) went bust and the creator, Norm Koger, has said he approves of the game being available as abandonware from the Underdogs. One of the best things about the game are the user-made scenarios on the net (try the wargame.com site) - I've played scores of Napoleonic ones and they are great fun.

I tried the Sid Meier game, but could not get into it - old stuck in the mud turn-based gamer I was. After immersing myself in TotalWar maybe I should go back to it?