Bravado is a set of free wargames rules for the horse and musket period. There are guidelines for both the American War of Independence and Napoleonic Wars for play. The rules employ an interesting mechanism where the players compete for initiative, deciding how much they will risk disaster in order to have another phase of movement or attack or time to reform their regiments.
Steve Burt offers a set of Napoleonic Wargames rules.
These Fast Play Napoleonic Rules are described by the author as DBA-esque via Fire and Fury.