I ran across an interesting book swap site called BookMooch recently. It's a "community for exchanging used books". Here's how they say it works:
1. Type in books you want to give away.
2. Receive requests from others for your books.
3. Mail your books and receive points.
4. Ask for books from others with your points.
I've never used it, but it sounds great. And--if you're like me, and have lots of books to give away, but don't really need to be acquiring new books all the time--they have an option to give your points to a long list of charities they work with. Now there's a good idea.
I'm sure there are other services out there like this. Has anyone used this one or any others?