It's not exactly steampunk, but in spirit it might be:
The Diamond Age, by Neil Stephenson. The reason it's "not exactly" is that it's more set in a potential future than past, with nanotech. It kind of is because of the dominant presence of the "Neo-Victorian" culture, and because the nanotech operates via tiny gears and so forth, which really lends that cogwheel tech flavor.
There was a fun looking tabletop RPG out many years ago called
Space 1899 that used a steampunk setting. Victorian ornithopters on Percival Lowell's Mars! I never did get a chance to play it, sadly. Too many games, too little time.
