Microsoft has just released the official Xbox Live app for the iPhone, iPod Touch, and iPad.
Here is the description from the App Store:
Take your Xbox LIVE experience wherever you go with the My Xbox LIVE app. Track and compare your achievements, connect with your Xbox LIVE friends, and change up your 3D Avatar. Review all your recent great games you and your friends love to play and compare achievements with them. Jump into our games hub to learn about the latest LIVE games and apps. Access Xbox Spotlight feeds, get breaking news from Xbox LIVE, game tips and tricks, gamer spotlight and much more.
You can download the Xbox Live app for free here.