This morning we just published a CodePlex project for our source control client. We've released the source code under the Microsoft Permissive License. The source code is already available, and the internal and external issues have been moved to the public Issue Tracker.
In addition to cpc.exe, we've also included a utility called tfc.exe, which works against arbitrary TFS servers. In the Beta 2 release of the client we will be publishing binaries for both cpc.exe and tfc.exe. The Beta 2 release will also enable the ability for cpc.exe users to get anonymous access to the source code of any project on the system, thereby closing a long-standing CodePlex feature request.