The Microsoft® Windows® Software Development Kit (SDK) for Windows (tools and samples run on Vista,as well as on Windows 2003 SP1 and Windows XP SP2) provides the documentation, samples, header files, libraries, and tools you need to develop applications that run on Windows.
The Windows SDK includes content for application development with the APIs in Windows Vista, including the .NET Framework 3.0 technologies: .NET Framework 2.0, Windows® Presentation Foundation, Windows® Communication Foundation, Windows® Workflow Foundation, and Windows CardSpace™.
This SDK is designed for use with Windows Vista (which includes Framework 3.0). The Windows SDK for Vista also supports creating applications for Windows XP, Windows Server® 2003 SP1, and Windows Server 2003 R2.
This download contains the SDK only. To build .NET Framework 3.0 applications for Windows XP or Windows Server, the .NET Framework 3.0 Runtime Components must be downloaded separately.
PS The Windows SDK is about 1.2 GB big and can be downloaded as a DVD ISO image as well.