The famed developer of CyanogenMod, Koushik Dutta, also happens to be one of the forerunners of app and feature development for the Chromecast. He has been instrumental in some of the first more advanced ideas for the device, including an early app for streaming local content from Android devices to the Chromecast.
His work was temporary put on hold for a bit when Google decided to restrict API access to select partners for a while. Now that Google has released the public Chromecast SDK for developers, he is already close to some new features for his AllCast app for the Chromecast. Koush recently teased this new feature which will be the ability to mirror an Android device display to a TV, using the Chromecast. Very slick!
More than likely this new feature will work just like his other app, Mirror, which allows you to screencast Android to an Apple TV. The above video shows off Mirror, just to give you an idea of how it functions. We don't know much more than that, but will keep you updated when we know more.