This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
You should be aware that many sites that offer books for download are actually pirating copyrighted works. I assume you do not work for free, so you should give authors their due and purchase books that you use. That said, there are several works available under very generous licenses which allow you to download a copy. One such work is How to Think Like A Computer Scientist.