The Microsoft Visual Studio 11 Beta SDK includes project templates, tools, tests, and reference assemblies that are required to build extensions for Visual Studio 11 Beta.
CREATED BY: Microsoft
SUPPORTS: Visual Studio 11
LAST UPDATED: 5/15/2012
By using the Visual Studio 11 Beta SDK, you can create tool windows, menu commands, editor extensions, isolated shell projects, and other extensions for Visual Studio. The SDK also helps you test and debug your extensions in an experimental instance of Visual Studio so that your primary development environment is not changed unexpectedly. After you install the SDK, you can use the shortcuts on the Start menu to find the online documentation, samples, and other developer resources.
Samples for building Visual Studio extension area available on the MSDN Code Gallery.
What is this? In short, if you want to extend Visual Studio 11, then you need this.
I know, I know, you're saying, "But the RC is just weeks away..." but still this might come in handy (I know it does for me) in the mean time.