There have been many questions about getting test result from third party test frameworks published to TFS since the first release in 2005.  Unfortunately the answer has been that you need to generate a file that looks like one of our test results xml (.trx) files and publish with MSTest.  However, with 2010 and the new TCM capabilities we now have a complete public API that gives you the ability to create create your own utilities to upload test results.

Publishing Test Results with VSTS 2010 TCM API, gives you a basic overview of the TCM API and some sample code to publish and NUnit results xml file to a 2010 TFS Server.