One of the annoyances of the Android Marketplace (for developers at least) is that there’s no easy way to get the info to use in your own applications. Fortunately some folks have reverse engineered the protocol used by the marketplace app to create an open source project that queries the marketplace servers. I’ve been fooling around with android-market-api, great project. I actually had issues with the latest latest code from the svn repo. But if I pull from the 0_3 tag I can compile my own programs that do things like run through the categories. Nice!