Lots of folks have asked for sharing in TFS version control.  While we don't support it and don't encourage it as a best practice, Rob Caron mentioned that Component Software has produced an application called TFSLinks that adds sharing functionality to TFS.  For those of you who can't live without VSS-style sharing, you might want to give it a try.

The TFSLinks product maintains the relations between shared files and automatically updates all instances whenever a new revision is checked-in to any copy of the shared file.

Shared files may be imported from your original VSS projects, or defined manually.