I'm proud to say that we've finally released ZenTest 3.0!
ZenTest has had a nice overhaul, is much better on working with rails, and has better support for naming conventions. unit_diff has been solidified into a scary monster I can't live without. New to the game is autotest, a continuous testing tool (originally for rails) that gives you near-immediate feedback as you develop and refactor. Oh, and it is now available as a gem and uses rake (so it should be a better citizen on Windows).
Please, check it out and let us know what you think!

Any tutorials on using ZenTest with Rails? Quick google search didn't come up with anything.