Whenever you login to Teamprise the TFS workspace is always the last workspace you used. To change workspaces: From the workspaces drop-down menu located in the Teamprise Explorer window menu bar, select a workspace. The Source Control view refreshes to the selected workspace view.
If you need to create a new workspace, see Creating and Removing a TFS Workspace. When you return to this view the new workspace is included.
Related Tasks:
Branching a version
Creating and removing a TFS workspace
Naming your TFS workspace
Adding a working folder mapping to a workspace