I've fought with RLS for 9 years now. I recently bought a Sleeptracker watch and I can't say enough good things about it! It works by measuring number of "almost awake" moments during the night, and computes average minutes in between these episodes. You keep track of these as well as other behaviors (exercise, baths, alcohol, caffeine) to find what helps or hurts your sleep. (Hot baths good; beer, bad ) It's a little pricey ($150), but has made a world of difference for me.
It also has an alarm that will wake you up within a half-hour window. It goes off based on your "almost awake" movements; that is, it goes off when you are easiest to wake up!
Has anyone else used this?