First, if you want to use VS 2010 with Team Foundation Service, you need to install a hot fix. http://support.microsoft.com/kb/2662296
Note 1: you need to install VS 2010 SP1 first.
Note 2: Regular Windows Update won’t pick this hotfix up. You need to manually install it.
If you already are using a workspace with VS2012 with TFS and you want to use the same workspace for VS 2010:
- Edit your VS2012 workspace and change from Local Workspace to Server Workspace.
- In VS 2010, you should now be able to see the workspace used by VS 2012. Select that workspace to use.