Atheists tend to be readers - with the exception of my esteemed colleague (Jack Jackyl). :) I have recently joined a website called Paperbackswap.
It seems like a really cool idea. Basically, you register as a member and list at least nine books that you'd like to clear off your shelves. In turn, you make a wish list of books that you'd like to get your hands on. If a book on your shelf is desired, you print the address off of the paperbackswap notification and mail the book to the person requesting it. In turn, if a book on your wish list is owned by someone in the PBS database, they will do the same in turn for you. You earn credits by the number of books you send. I've sent out four, so far, and have managed to get two in return...my wishlist is a bit obscure, so I imagine it will take a bit longer.
If you join, please list me (Possummomma) as your referral - I get a book credit.
As I said, I think this is a really cool idea and makes sharing information easier.