Timeline 300 is a set of steam-punkish rules for a now-defunct line of miniatures. The rules, though, can be applied to other figures.
steampunk
Malifaux 2nd Edition Rules
The second edition Maifaux Rules are available free for the downloading.
Wargaming In The World Of The Difference Engine
James Clay has written a fine article on wargaming in the world of the Difference Engine.
For those who don’t know, The Difference Engine
is a novel by William Gibson and Bruce Sterling that takes the reader to a Victorian world in which Charles Babbage’s Difference Engine drives cybernetic steam engines. While I did not enjoy it as much as Gibson’s Neuromancer, it still was a good read.