I have known about this site for a while, but I just realized lots of people don't. Gutenberg.org is a site with a collection of over 18000 free books.
Here's one I downloaded just recently: Albert Einstein's Relativity : the Special and General Theory
Just thought I'd share this one with you

Thanks psYchotic one! Great resource man, never knew about it till now. Kudos!

thanks for the free books... it really helps me a lot.