The goal of Roslyn is to create a "compiler architecture that is amenable to use as a foundation for modern tools." At this point it's unclear if Roslyn will be a part of Visual Studio 2012, or some future project. Since the discussion will be part of a Microsoft Research event, it may be likely to be a year or more before it becomes part of an official product.
Microsoft's "Roslyn" compiler-as-a-service (CaaS) project has not received much press, and developers haven't heard much about it--yet. But at the annual Microsoft Research Faculty Summit this week, developers will learn how they can use Roslyn to expose the code analysis from Visual Basis and Visual C# compilers.