Got this from one of the Thrifty Homeschooler members. Very cool:
Homeschool Book Swap
It's a place to find or give away books for free or for postage. I thought it would be nice to have a place where people could list books they needed or books that needed a new home! It's still a small group, so the more people who join the better!
Check it out!
Another site to donate to is: http://www.booksamaritan.com/