"TitleZ makes it easy to see how a book or group of books has performed over time, relative to other books on the market. Simply enter a search phrase, book title, or author, and TitleZ returns a comprehensive listing of books from Amazon along with our historical sales rank data."
TitleZ (for all you obsessive-compulsive masochists out there) is free for now. You just have to register.
Oh, no! Another toy!