Here’s the summary of a white paper that we just posted to the MSDN Library:
Visual Studio 2005 Team System Modeling Strategy and FAQ
Summary: Customers and partners are keen to understand Microsoft's strategy for model-driven development and its support in Visual Studio Team System. When we explain our strategy to them, they frequently express interest in some of the same topics, and raise some of the same concerns. In this document we set out our strategy for model-driven development as a series of questions and responses that address these topics and concerns. The first five questions deal with the main pillars of our strategy, which we have described with detailed answers and explanations. Other frequently asked questions are gathered in a conventional FAQ in the last section.
Go read it.