Anthony asked in one of my comments where to get ebooks. Aside from Amazon (but you have to look hard) and the other main book outlets on the web, I use the following alot.
http://www.gutenberg.org/wiki/Main_Page This is a non-profit outfit that's transcribing out of copyright material to electronic format on the web. A lot of the classics that I've read over the last couple of years are from here. If nothing else, contribute a bit, it's a good thing.
http://www.mobipocket.com/en/HomePage/default.asp?Language=EN This is the online store for the ebook reader I use on my PC. Some good stuff, some weird stuff too.
http://www.baen.com/ A lot of my favorite SciFi writers are part of Baen Publishing. They've got a free library and a link to http://www.webscription.net/default.aspx which carries several publishing houses output.
I shall now go off on a tangent.
Eric Flint, the "web librarian" of Baen's free library has a treatise, if you will, about making these books freely available. Read it, it's good, just go to the free library and click the home link.
Edit: Alan over at Snarkybytes just pointed me to Feedbooks. I just might sign up for an account. I was looking at the Stanza reader for iPhone earlier today since Mobipocket hasn't ported over theirs yet.