TFS2008 supports nested branches, TFS2010 doesn't (new branching model).
SO: Team Foundation SDK - programmatically access branch data
MSDN Blog: What's New in TFS 11
Version Control: Workspace Improvements, Merge Enhancements, Pending Changes
Version Control Model Enhancements in TFS 11
local workspaces will be the default. In local workspaces TFS assumes that your client is “the master” and TFS needs to understand the changes that you make there and “do the right thing”. In configuration management parlance, it’s called Modify-Merge-Commit style version control – or some might think of it as “the Subversion style”.
One of the implications is that you no longer need to use a tool with version control integration for the right thing to happen (because the file system is the master) – so you can use Notepad or any other tool and TFS will work the way you’d expect. The local copy is the master and TFS tries to just “do the right thing”.
This might mean less housekeeping that Git-Tfs has to do, assuming that TFS "does the right thing" (Place your bets folks!)