The TooFatLardies produce many excellent rules for 19th Century wargaming, available either as stand alone products such as their American Civil War set They Couldn't Hit An Elephant and Kriegspiel, or as extended articles in the various Summer and Christmas Specials.
In this section of the Vis Lardica site, you will find all the various 19th century wargaming pages that I have produced over the years, originally appearing on the SirGarnet website, and then on the Vis Imperica website.