I haven't used selenium RC with TFS but I have used WatiN a lot so I can share my experiences with that, and no Microsoft Test Manager.
Firstly, what is your goal with Selenium RC is it to scale out your execution, or just use C# as your environment?
Firstly I would look into Selenium 2, as opposed to Selenium RC to see if that fits your needs. For the most part, Selenium 2 will supersede Selenium RC and it has a much cleaner architecture.
I personally write my tests as VS2010 unit tests, and then use the unit testing infrastructure to execute my tests.
I have the "quick and dirty" method of checking out the tests and building them on all my test machines and then manually running them in the unit testing tools with a test list, then uploading the results back to the server.
Another way is to use the VS2010 test agents to push out the tests remotely and execute them that way, but it requires controllers and agents to be configured and running.
One of the big challenges with running tests as part of the build is the need to have an "interactive" session for the tests to run. Personally, I just run developer unit tests as part of the build, and then manually kick of the tests after I have run a build verification test using humans.
I find this hybrid approach works really well.