Along with the new tools we’ve added in VSTS 2010 for testers comes the TCM.exe command-line application.  This command-line isn’t intended to be an alternative for everything you can do in Microsoft Test Manager (MTM) but rather to fill some gaps and enable some of the less common scenarios that still may be important for some testers. 

You can get a general overview of TCM.exe over on MSDN in this article.

Some examples of things you can do with TCM.exe include:

• Create an automated test run that contains test points across multiple test suites.
• Create an automated test run without specifying a Team Build (you can specify the build directory where automated test assemblies are picked up directly).
• Publish results from a trx (MSTest / VS run results file) against your Test Plan.
• Import VSTT Unit Tests (or even other VSTT test types) from your test assembly into your team project.  Creates a Test Case work item from each Unit Test (given some user specified constraints on what to import) and creates the association with the automated unit test for you.  You can also sync this set of imported tests with a specified Test Suite.