I'd like to share with you a problem on VS 2003 ONLY and not in VS 2005.
The bug as follows; if you install MSSCCI 1.2 Provider for TFS in VS 2003,you can't switch to VSS as a source control.
This problem will affect you because you can't open any project binded to VSS as a source control;it takes TFS as a default source control even if you change it from the TOOL-> Source Control Menu in VS 2003.
NOTE : This problem ONLY exist in VS 2003 and i tried in VS 2005 and its working fine.
I submitted this to VS Product Team as a bug;for now;to solve the problem;you have these options :
1) Either to change in the registry of your machine (I DONT RECOMMEND THAT).
2) Use Third party tools "SCP Selector" , here is the download url :
Hope this is useful :)