NCrunch is an automated parallel continuous testing tool in Visual Studio.
Your tests are run in parallel as you code, giving you real time feedback on failing tests, code coverage and long running code called hotspots.
I love it and think it should probably be built into Visual Studio but for now download it and give it a try – you won’t regret it!
Home page for NCrunch: http://www.ncrunch.net/
Sample project with tests: LibrarySystem.zip