ReSharper UnitRun

I'm all in favor of good tools when I can find them, even better when they are free (as this one appears to be).

But JetBrains has released ReSharper UnitRun for down.
http://www.jetbrains.com/unitrun/

If you already use ReSharper you know how good of a tool this is already.
If you don't user ReSharper, this is one of the best features in it (next to automatic code profiling).

So, if you are doing Test Driving development, check it out, it is worth the download.