If you're using Litmus on a Mac, this is a tip you'll love. It's now possible to run Litmus as its own separate application, with built-in system notifications when your tests are complete. I'm using it this way myself and I find it really useful.

I've recorded a screencast to explain how you set it up. Watch the video, then download the resources linked below to get started.
Litmus native Mac application tutorial (2:30, 13mb Quicktime movie)
- Download Fluid
- Download the Litmus icon
- Download Growl (you might already have this installed)