I did some physical and occupational therepy a few years ago for neck/shoulder pain caused by overuse on the keyboard.  The OT did some elastic band exercises, which were helpful, and some electric stimulation, which was not.  The PT did some stretching of my neck, I laid on a funky table and he would hold my head in certian positions for a while.  He also gave me the advice to lay on the floor and put my head on a really thick book (4 to 5 inches) and to stretch my neck that way.  I actually use a futon that is pretty low--just put the back of my head on it while lying on the floor and let it "hang" and stretch for 45 seconds or so.  That has helped me so much, just doing that once or twice a day.  That and making sure to stretch and move my neck and shoulders several times a day--until I started doing this I didn't realize how long I would stay motionless.  Also something I have been doing daily that helps is to do shoulder shrugs with dumbbells in my hands.  I use 8 pounders and do 2 sets of 25 shrugs.

Oh--and one other thing I have done was to switch my mouse to the other hand.  It took a few days to get used to, but was fine after that and helps to take the pressure off my right hand, which used to do the mouse, number pad plus typing.

Hope that helps some!  That kind of pain is awful, especially when it starts to affect you outside of work.