Get it right here.
XNA Game Studio Express is a new offering, targeted at students and hobbyists for game development. XNA Game Studio is based on Visual C# Express 2005 and lets developers target both Windows and Xbox 360. XNA Game Studio Express contains the following:
The XNA Framework Content Pipeline, which is a set of tools that allow developers to more easily incorporate 3D content into their games.
The XNA Framework, a set of managed code development libraries that make it possible for game developers to be more productive when creating games for Windows and Xbox 360.
Game Studio Express also contains a full set of documentation, how-tos, and starter kits that demonstrate how best to use the content pipeline and XNA Framework.
This initial beta doesn't support developing games for the Xbox 360, that's something for the final version as Microsoft don't release beta code for the Xbox 360 but that will be here by the end of the year.
As with Microsoft's Visual Studio Express range this will also be free. However if developing for the Xbox 360 there will be a $99 yearly subscription to the "Creator Club" which can be purchased over Xbox Live Marketplace this will allow you to deploy your games to the Xbox 360.
Checkmate Sony, checkmate. No platform can exist without my new upcoming Xbox 360 title; Shape Wars II: The Revenge of the Pwning Uber Retro Shapes.