Moving ahead with its Xbox SmartGlass project, which aims to use your smartphone or tablet as a second screen in the Xbox 360 experience, Microsoft is already providing access to the software development kit for select partners with “agreements to develop Xbox games or entertainment applications.”

The SDK, available on the Game Developer Network for registered partners and employees, includes the Xbox SmartGlass Studio environment for building "SmartGlass Activities" as well as a Javascript application programming interface designed to work across Windows, iOS, Android and Windows Phone. Microsoft also provided a library of sample code to get developers started with some guidance.

Although developers will be able to start tinkering with SmartGlass right away, users will have to wait until the fall when it launches as a new application for Windows 8, Windows Phone, iOS and Android.

SmartGlass will work wirelessly to connect your Xbox 360 to your portable device, and provide side content to a game or a TV show. During its E3 presentation, Microsoft showed how you could use a tablet draw plays on Madden while the actual gameplay happens on the TV screen, as well as an interactive map pinpointing where the action was taking place during an episode of Game of Thrones.

It can also be used to navigate videos and movies being viewed on the TV screen, stream videos from Xbox Live to a tablet or smartphone, or as a virtual keyboard while surfing the web on the TV screen.

In many ways SmartGlass is Microsoft's answer to the Wii U's upcoming tablet-equipped GamePad, only it offsets the costs by using touchscreen devices that players might already own. Ultimately its success will largely depend on how well developers make use of a secondary screen to enhance the gaming experience, while at the same time not degrading it for those without a tablet — or those who don’t care to use one.