Check out http://www.microsoft.com/xna/ and Tom Miller's Blog
Unfortunatly, I don't hold out hope that it will allow us homebrew developers to play with it. It would be cool if we could created XBox Live content! :)http://www.kinlan.co.uk/opml/a0b9f8629fb18a2c.opmlXNA FrameworkMicrosoft unveiled the XNA Framework at the Game Developers Conference 2006. The XNA Framework is an exciting new development and execution environment which will allow game developers to more easily create games which run on the Microsoft Windows and Xbox 360 platforms. It is being designed with a unified set of class libraries which will allow for maximal re-use of code and assets across target platforms. A custom version of the Common Language Runtime is being built to enable the execution of managed code on an Xbox 360, and at GDC the XNA team showcased some exciting demonstrations of games which were built on an early version of this technology.