Check out Rob's blog announcing the new branding for Team System 2008. In it, he writes:
Since we released Visual Studio 2005, we’ve heard from you that the capabilities of each of the team editions don’t always map to the way you define roles in your organizations. To simplify the naming and respond to this feedback, we’ve renamed the team editions to remove specific role names. Of course, this doesn’t mean we’re changing Team System’s charter – it’s still designed to help everyone on the team collaborate together through integrated tools, processes, and guidance.
These changes will be apparent in Team System 2008 Beta 2 available soon.