Over the weekend, our team released the first fully supported version of the Team Foundation Server Integration Tools.  This suite of tools has been developed by the TFS product group with help from the Visual Studio ALM Rangers to provide a comprehensive package to help teams that are migrating from 3rd party ALM tools to TFS.  Included in the release are adapters for TFS (2008 and 2010), Rational ClearCase, Rational ClearQuest, a file system based version control adapter, a readiness package including documentation, guidance, and case studies, GUI tools for configuring and running migrations, and sync monitoring tools and reports. 

You can download the tools here: http://visualstudiogallery.msdn.microsoft.com/en-us/5a8d1703-7987-4081-ba2f-9d0b68b0ed3e

Any questions or feedback on the tools can be given through the TFS Integration forum on MSDN.

5/11 - It seems that the last update of the TFS Integration Tools broke my link above.  The Migration and Integration Solutions page should always contain a working link for the TFS Integration Tools moving forward.