Facebook reported today at the Mobile Web Wars that their Facebook iPhone OS application has 1 million users. This is totally amazing, if true. Considering that it has never been the most popular free application in the store there must be other applications with even more users.
Hopefully Apple will release some statistics soon on sales in the App Store. The first couple days of the App Store being open stats could be gathered in the mobile App Store. That was cut off by Apple, quickly.