Microsoft has released Visual Studio 2008 SDK Version 1.0
>> Visual Studio 2008 SDK
The Visual Studio 2008 Software Development Kit (SDK) 1.0 includes tools, documentation, and samples for developers to design, build, test and deploy extensions for Visual Studio 2008. You can also use the VS 2008 SDK 1.0 to create custom tools environments based on the Visual Studio 2008 Shell.
>> Visual Studio 2008 SDK