A really neat site that lists all free Kindle books and lets you search Amazon for Kindle books; but perhaps its best feature is the Kindle Price Drop tab where you can list books from your Kindle Wishlist together with a target price drop and the site will email you if/when Amazon cut the price by that amount. Very useful given that Kindle book prices can rise and fall dramatically from one day to the next. (NB you have to put in how much you'd like to see the price fall by, not your target price!)
Have just noticed that the above has changed, it now says -
Existing Users: Please note that we have changed our 'Notification Threshold' to a 'Notification Price'. You can now specify the
price at which you would like to be notified of a price drop rather than the amount the book needs to drop in price
So it may be an idea to check your lists and alter any prices to reflect the above!