The Book Burro is an extension built for Firefox and Flock. After the typical extension install (1 minute), go to Amazon or some book selling site. Once you on the page of a book, you will notice this appear on the top left of your screen:
By clicking on Book Burro, it will display the price of competing stores and even tell you if your local library has the book in stock. Here is a sample of the results when I looked up War and Peace on Amazon:
Pretty slick. On the screenshot, you will notice the Tools on the top right. Once inside, you can add/remove stores and even associate your searches to your zip code. If a local library has the book available, it will display the library and tell you how far away it is. Keep in mind that they are still adding to Book Burro so the library list is relatively limited at this point.
Check it out at Book Burro. [via del.icio.us]
Firefox extension: Book Burro Saves money on Books
