There are number of sites out there that give you some stretches or exercises you can do at your desk (it’s a good idea to take breaks every 15-30 minutes as a preventative precaution against RSI). I thought I’d share this one. It’s quick and easy, with cartoons to illustrate the stretches. I love the little warning at the end about being careful if you have chairs with wheels.
The main site has a number of helpful carpal tunnel syndrome related links as well.