(Thanks to my co-adviser Peter Lyman for the Ibuprofen and the wrist braces!)
So, ever since I made the move from Astronomy to a discipline about a zillion times more computing intensive (SIMS), I've been typing so much that I've started to get what's known as RSI, or the thing that eventually turns into carpal tunnel syndrome.
But, I've conquered it through some serious scientific experimentation. I've tested a lot of different things over a period of a few months. One thing seemed to help particularly well. What works the best? Push-ups. (Interestingly enough, I came to this conclusion realizing that I never had trouble with this during a particularly typing intensive class in undergrad. ... but back then I was doing triathlons and running, swimming and biking quite a bit.)
Seriously. Here's the sure cure for your typing woes: Every morning, when you get up, do as many push-ups as you can in two minutes. I can do 80 on a good day... I know some people who can do a couple and I know people in the military who could do about 150.
It's best to try and cement this practice into your daily routine like you (hopefully) have done with brusing your teeth. While you're at it—if you can spare 4 minutes out of your day—you might want to do as many sit-ups (and not the old-school kind, but crunches) as you can in two minutes as well.
To ensure that I haven't corrupted the experiment, I should probably describe what else I did in the process and how much they've helped.
DimpGel laptop pads from shinza. These things easily sit underneath your palms on top of your laptop. These help quite a bit an they may be all you need (if you're not in to push-ups).
Ibuprofen. One of man's better inventions/discoveries. Ibuprofen can reduce swelling (which is what causes typing-related RSI) quite a bit. Be sure to take 600mg of Ibuprofen which is usually about 3 tablets. You might want to buy a gignatic bottle of this stuff from a nearby drugstore. You can usually get a 500 tablet bottle at a large grocery store.
Pay attention to how you're sitting. If your elbows are not supported that's a good sign that you're not sitting right. Plus, you should have the keyboard such that your forearms are parallel to the groud (if you have a laptop get an ergonomic keyboard that you can use and have the laptop at a higher level so that you don't have to look down at the screen).
If you're wrists/hands hurt really bad and there's no hope that you'll be able to stop typing anytime soon (like right now finals season), get a pair of wrist braces that you can wear at night to make sure your hand is kept in a "healing conducive" position.