I was just wondering if anyone could recommend any fictional or non fictional books about steam punk?

Thanks in advance!

I haven't read any of it myself... well some of what i have read probably fits into the broad category, but i'm not familiar enough with the genre to recommend any. However, there are a lo of good suggestions on this thread:

http://www.librarything.com/topic/74535

Start with the best of the best: Perdido Street Station by China Mieville!

Extraordinary Engines is a steampunk anthology, so there's a nice sampling of the genre there.

These are the common books tagged as steampunk:

The Difference Engine by William Gibson (324)
Perdido Street Station by China Mieville (271)
The Scar by China Mieville (150)
The League of Extraordinary Gentlemen, Volume 1 by Alan Moore (114)
Iron Council by China Mieville (105)
The Diamond Age: Or, a Young Lady's Illustrated Primer by Neal Stephenson (101)
The Court of the Air by Stephen Hunt (85)
Steampunk by Ann VanderMeer (81)

YA suggestions:

Skybreaker and Airborn both by Kenneth Oppel

#3

Except some people don't think that China Miéville's Bas Lag books are steampunk at all. They may fit in to what some people term Gaslight Fantasy but Miéville calls them New Weird. For me (yes, I'm on of those 'some people') I don't think secondary world fiction can be steampunk, and even if you do allow cannot be considered a typical exemplar of steampunk.