BookMooch
This is a wonderful new thing i discovered on the net. A person has started a website where people can join for free and share their books with other users. You can ship your books to a user... gain points and use these points to order books from other users. Simply awesome to say the least. And the best part is that the users are not just US or UK based, but instead almost every country, including India is represented there.The website is : www.bookmooch.com