I've joined BookMooch, which is a fun little website, if you have books that you no longer want. BookMooch is an book swapping website, where you send your books to other people, and get ones you want in return. Great if you don't want to go to the hassle of selling the books that you no longer want. I personally like BookMooch better than some of the other websites, because they happen to have more of the books that I would want to read. Check it out.