I actually had a sore nose-picking finger. Seriusly. Using the mouse made my finger absolutely unbearable to use.
One thing I found to cure wrist-pain from the mouse is to put it on your lap. Sure I looked like a dork at work, but it was really comfortable.
Also, lifting yourself up (neck chin ups or whatever) really helps with nerd-posture.
And that excercising dude is right. Moving about helps heaps. And lastly (but quite drasticly) you can always try not using the computer. I know it sucks. You can't IRC like that. Thats why I got a PDA.