According to an Electronista report, Microsoft will announce its plans to port Silverlight to Xbox 360 at the MIX11 conference next week. According to leaked information, the feature has supposedly been in development for several months and could bring a higher level of integration between the Xbox 360 and Windows Phone. More importantly, a tipster speaking to WinRumors suggested that Microsoft might bring an app store for the Xbox 360 that would let developers easily port WP7 apps over to the larger screen.
Windows 8 may also have its own app store "out of the box" and would emulate the Mac App Store. Microsoft has not confirmed this story.