Here's a blog post that details the improvements for testing in VS, TFS and Microsoft Test Manager in SP1.  I've got an outstand ask to find the list of improvements in the Framework too.

http://blogs.msdn.com/b/amit_chatterjee/archive/2010/12/10/visual-studio-2010-service-pack-1-beta-released-information-on-test-and-lab-management-changes.aspx

Brian