SmartGlass will be a companion app for your Xbox 360, and what ever the next Xbox will be. At first glance it will just be an app that will let you control the Xbox, the apps, video playback and the usual controller type functions that you may have bought a remote for. You will be able to start, stop or pause a movie or music from your phone, resume it from your tablet and change tracks on your phone as long as you are connected to the same Wi-Fi network. SmartGlass will also pull relevant information about the movie, its actors, the band and other information and display it on your phone or tablet while showing the movie on your TV. I particularly like how you can find something to watch on your device and then send it to your Xbox and it plays on your TV. It is like Samsung’s AllShare function without the need to buy adapters or a new TV.
The functionality is supposed to extend a bit further though. Offering up a second type of screen for your gaming needs too. For instance, Forza Horizon will have a GPS map of the race track displayed on your device. Pocket-Lint was also told that you can use the app to line up the next track for Dance Central 3.
Not to mention full support for the Browser for Xbox that is on the way. You will be able to use your device for pinch to zoom, as a touch mouse and use the keyboard for typing.  Yes, it is coming for iOS as well and will be found on Windows 8, Windows Phone 8 and Windows RT also.
Kind of nice to see Mark Budash, software engineer at Xbox, hold up a Samsung Galaxy S III in the video below.
Source: Microsoft Blog and Pocket-Lint