Visual Studio 2010 ships with the DSL Tools and T4 runtime in the box in every edition since it is used by other tools in Visual Studio, such as the Linq to SQL designer. The DSL Tools SDK (for the DSL authoring experience) is shipped separately and depends on and exploits features in the Visual Studio SDK. The Visual Studio 2010 DSL SDK Beta 1 provides tools and templates for building Visual Studio Domain Specific Language designers for Visual Studio 2010 Beta1. By using the Visual Studio DSL SDK, you can build your own graphical or form-based designers for Visual Studio 2010 Beta1.
Download: Visual Studio 2010 DSL SDK Beta 1