Today Microsoft, out of the blue, released a new app for the iOS devices tantamount to their newest Xbox Live update. My Xbox LIVE can be found as a universal app in the App Store which will allow you to access some account features from your iDevice.
The home tab shows your the latest Xbox Live videos and news. Swiping left will show your avatar, send/check messages and beacons. Beacons is the new feature for Live that lets your friends know you want to play a certain game and need players. From this tab you can also change your avatar's features and clothes in a nice 3D UI. Finally, you have the games tab which shows all of your games and achievements.
My Xbox LIVE is free in the App Store and is a great looking app. If you own an Xbox and an iOS Device, this is something you should check out.
App Store - My Xbox LIVE