oh man...

Gail Carrier's Parasol Protectorate series

Most of Jules Verne's work

League of Extraordinarily Gentlemen (its a Graphic Novel now I think.)

There's also this link to the 12 best steampunk novels http://www.flashlightworthybooks.com/Best-Steampunk-Books/403

and this little reading list as well http://wisb.blogspot.com/2009/01/steampunk-reading-list.html

its a start anyway.