In-app billing has quite a few possible uses, from eliminating the need for separate trial and full versions of apps, to letting developers sell virtual goods and upgrades within apps. Developers will surely come up with lots of novel ways to make use of the new system.
One app already using in-app billing is the long-awaited Tap Tap Revenge. We’ve included links below to a couple other that have also already implemented in-app billing. Whether you’re a user or developer, let us know in the comments how you like the new functionality.