Now this topic was closed due to warez, but wait a tic... There are leagal ebooks out there. And MSN and Google are about to release MANY books on the net...
Now this is a basic google search http://www.click-now.net/ebooks02.htm http://www.maththinking.com/boat/computerbooks.html
as for pay for sites, http://www.books24x7.com
is awsome. Now sure how expensive it is as my job covers it for us. But they have every thing.
There are also many good text files on the net. Try a search like
I learned quite a bit from free online resources. This place was the main one.