This morning we delivered the final version of the patch to Team Explorer 2005 that enables it to work well with a TFS 2010 server.  Of course, it will also still work well against a 2005 or 2008 server.  You can download the update here:

http://www.microsoft.com/downloads/details.aspx?FamilyID=22215e4c-af6f-4e2f-96df-20e94d762689

and, of course, the update for Team Explorer 2008 has been available for a while:

http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=cf13ea45-d17b-4edc-8e6c-6c5b208ec54d 

Good luck with it and let me know if I can help you,

Brian