Maybe this should go in the deals thread, but a friend of mine posted on facebook a stack 25+ children's books she bought at a library sale for $6.25. Good ones too - Sandra Boynton, Dr. Suess, Curious George and others. When I asked her about it she sent me to this website.
http://www.booksalefinder.com/index.html
Thought it was a great resource I can't wait to check out a local sale near me next weekend