Game developer Bungie (the folks behind the Halo series, originally scheduled for release on Mac but also the game that eventually became the keystone of Microsoft's game console) has released an official iPhone app, just in time for the company's 20th anniversary. Bungie Mobile is available for free on the App Store, and allows you to browse through your and other players' Halo information, see official Bungie news and just generally enjoy the heck out of one of the best gaming developers around.
Additionally, when you sign in to the app with a Bungie account, you can get blue flames for your helmet in Halo: Reach, a special graphical effect previously reserved only for Bungie employees. Good deal.
Bungie is doing all of this to celebrate the company's 20th anniversary on July 7, so happy anniversary to them. And now that they're out from under the thumb of a Microsoft partnership, hopefully we'll see even more Apple-related releases in the future.