How to update your TFS Workspace after CodePlex upgrade to TFS2010
Posted by Guardian in Visual Studio on Tuesday 27 July 2010 at 12:01 PM
Recently CodePlex updated their TFS to the 2010 version, during the update your reference TFS server may have changed name (like it happened for Dexter, our original TFS server was tfs05.codeplex.com and now it is tfs.codeplex.com).
To switch to the new server all I did was, open your solution in Visual Studio, it will open in offline mode due to the fact that the old TFS is no more accessible.
After that go to: ‘File --> Source Control --> Workspaces...’
You will be prompted with a dialog that asks for a new TFS address and new access credentials, take those from your CodePlex project website.
Once connected a new Dialog Box will open allowing you to select the project to which link your solution among all the Team Project Collections available to your account.
Select Connect and check if your workspace has been associated correctly.
To make the change fully effective, close and reopen your solution, you will be asked if you want to ‘Go Online’.
That’s all you need to do in order for having your TFS integration work again after the CodePlex upgrade.

#1 da http://www.codewrecks.com/blog/index.php/2010/07/27/codeplex-is-upgradedhow-to-map-to-the-new-server/
Codeplex is upgraded–how to map to the new server