Dan Brown offers A l’Ombe des Aigles, a set of free miniatures wargaming rules for Napoleonics miniatures.
A Near Run Thing is a set of Napoleonics rules by Peter Hunt of the Hong Kong Society of Wargamers. From the members list, it seems that Hong Kong has quite a thriving miniature wargames community.
Back to the rules: A Near Run Thing apparently once was available as a commercial set, but now is revised and available on the net. Peter Hunt writes:
Herbert Wong written “March to the Sound of the Guns,” a Napoleonic wargame that is a variant of Games Workshop’s Warmaster miniatures rules. Warmaster is a generally good set of rules that borrows heavily from Fire and Fury and some other historical sets. Of course, Games Workshop would never admit that. Heck, they don’t even admit that there is a miniature wargaming hobby outside of the “Games Workshop Hobby.”
The Jackson Gamers have these free wargames rules for Napoleonic skirmishes. The best part: the rules are just one page long.
From Matt Fritz comes this set of rules for using wargame miniatures to replay the fight for Hougoumont from the Battle of Waterloo.