Handheld Learning

I found this very interesting and regularly updating interactive analytical chart with data regarding Apple's App Store:

http://projectx.mobclix.com/appstore/

By clicking around you can find out how many applications are currently available and how they're divided between free and pay-for app's as well as how applications are divided between categories.

Education, games and entertainment are amongst the main categories.

Since opening in July 2008, more than 500 million applications have been downloaded from over 15,000 applications now available.