darthspudius: Yeah that is good advice there. I'v been wearing braces etc whilst trying to work on the positioning of my PC parts. With my back/neck issues, this is like icing on the bloody cake lol.
I would first say, be careful of diagnosing RSI as carpal tunnel. Are you actually sure it's that, because there are other forms of RSI, that require other forms of treatment. Carpal tunnel is almost the "bogey man" of repetitive strain injury as it's permanent damage to the ligaments.
What is your current layout of your PC (possible a picture would help). If you're using a laptop without a main screen then that's first call for your neck problems. When I was at a firm that was very "hotdesk" oriented, every time I went laptop only I stared getting neck pain. So I'd go and requisition a stand and usb keyboard, pain went away in no time.
As for arms and hands, forearms for me tend to be tend to be incorrect typing practices. I find I stretch for the keys while holding SHIFT (just did it then) rather than hitting caps lock. That's one of the killers for the typing, it holds your little finger in place on the SHIFT key, forcing an unnatural stretch with the rest of your hand. That tends for me to be felt in my forearms, and across the joint of my index finger.
For your wrists, it's most likely keyboard and mouse setup that you need to focus on. It's positioning and elevation that matter. Those wrist supported mouse mats worked quite well for me, but the best solution is to go ambidextrous on the mouse. It sounds extreme, but if you are scared about this (and you should be), then start using your mouse in your off hand. It is very difficult at first, and easy to think you'll never get it, but after about 2 weeks you're capable (though a lot slower), and from there you build pretty fast. It's the ability to just switch hands, when one is hurting, that has saved me from having to leave the programming profession. As they say, a problem shared is a problem halved.