There are a bunch of exercises that you should do, and the one thing to remember is NEVER STRETCH. When doing hand exercises go to the point where it's about to stretch then hold it an wait for the muscle to relax.

"Conquering Carpal Tunnel Syndrome" by -Butler is good.

Also as kevin suggested, get a tablet. I use a trackball mouse and it works great. It's less stress on the hand cause there is no wrist movement. Also make sure you are typing correctly and sitting up right.