I've been fighting this on and off for years. I've come to the conclusion that whenever I become lazy my hands and neck and eventually my back hurts. Lazy, meaning that I don't stretch and take breaks often enough. Also more importantly exercising, it's is the biggest and best solution. I don't mean lifting weights/running, I'm talking about something like Yoga. Call it girly all you want, it does miracle work for lazy folks like us that spend way too much time in a chair.
As far as stretching goes, take a look at this:
http://www.eatonhand.com/hw/ctexercise.htm
and just google "wrist stretches for carpal tunnel" and you'll get plenty of useful results as well as video tutorials on youtube.
Keyboards, Mice... I've used pretty much all of them. I even went out and bought a ~$1k ergonomic chair, changed desks...etc.. I figured that if my career was in danger I would need to invest a significant amount of money to recover it so that I could continue to work. So I've probably spent hundreds in different mice and keyboards. Ergonomic devices and furniture are great, but they are a temporary solution. For long term results, just don't be lazy.
Do three things to help and get rid of wrist pain:
1. Take small breaks throughout the day (or find a Rob).
2. Exercise
3. Stretch.
In my opinion, these help the most.
One note, if you're just starting to try and remedy your pain and you can't work at all, try switching the mouse to your left hand. This helps a ton and it'll only take you a bit to get used to it.
Hope this helps someone as much as it has me.