What’re some good sites for ebooks?

Anybody know of any good sites where I could find ebooks? wbb is always the first place I check but most of the stuff on here is fiction.
I’m trying to find a book called Diffusion of Innovations for my new kindle but I figured I might as well start collecting some good ebook /torrent sites for future reference.
Thanks in advance!
Answer #1
http://www.mobilism.org/ has quite a good ebooks section
http://www.drinkmalk.com/stanza/ is quite good, but is mostly fiction, and is intended to be access from an iphone or android, so you will need to search their forum for the desktop program to download from them
Answer #2
www.esnipes.com, register and search for the ebooks you want
Answer #3
gigapedia is always my first stop when i’m looking for a new book. and yes, they have the one you’re looking for (PDF):
http://~ Disallowed ~/mgl1byo/Diffusion%2520of%2520Innovations%2520%25283rd%2520ed.%2529.rar
there are a few (private) ebook trackers out there like bibliotik, myanonamouse and bitme. but to be honest, they’re not so exciting…
Answer #4
http://gigapedia.com/
Answer #5
Thanks guys, great help!