Track the sales of your books at
http://www.rankforest.com
The majority of the site can be viewed anonymously (ie, without an account). Taking 8 seconds to get an account enables you to add books, build a personal page to promote yourself, and create a collection of items for fast tracking.
Here's an example of a 30-day chart:
http://rankforest.com/detail/0764596411/30
The site is still pretty young. For those of you that create an account, feel free to leave some comments on my personal page
http://www.rankforest.com/user/steven. I'd love to hear some suggestions for features.
Thanks!