Microsoft XNA Game Studio Express is a revolutionary new toolset and technology which makes creating great video games for Windows-based PC?s and the Xbox 360 console (with an active XNA Creators Club subscription) easier than ever.
System Requirements and Prerequisites
Only supported on Microsoft® Windows® XP SP2 (all editions) at this time. Windows Vista will be available only in a future beta release of XNA Game Studio Express. Hardware requirements are identical to those for Visual Studio 2005 plus a graphics card that supports DirectX 9.0c and Shader Model 1.1 (Shader Model 2.0 support recommended). This release requires Microsoft Visual C# 2005 Express Edition to be installed before proceeding. You can install Visual C# Express from the Visual C# Express Download Page. However, other members of the Visual Studio 2005 line of products, for example Visual Studio 2005 Professional, can co-exist with XNA Game Studio Express on the same computer.
Microsoft XNA Game Studio Express 1.0
XNA Game Studio Express Readme
XNA Team Blog
Only supported on Microsoft® Windows® XP SP2 (all editions) at this time. Windows Vista will be available only in a future beta release of XNA Game Studio Express. Hardware requirements are identical to those for Visual Studio 2005 plus a graphics card that supports DirectX 9.0c and Shader Model 1.1 (Shader Model 2.0 support recommended). This release requires Microsoft Visual C# 2005 Express Edition to be installed before proceeding. You can install Visual C# Express from the Visual C# Express Download Page. However, other members of the Visual Studio 2005 line of products, for example Visual Studio 2005 Professional, can co-exist with XNA Game Studio Express on the same computer.
Microsoft XNA Game Studio Express 1.0
XNA Game Studio Express Readme
XNA Team Blog