T-belt/water pump replacement is kind of a big project, one my dad and I are working on atm.
http://groups.google.com/group/rec.a...ace+2001+jetta
You won't have to remove the alternator, but you will have to remove the passenger side motor mounts, which means you'll have to jack up the engine and transmission, so have a friend or two on hand and be careful. also, make sure you follow the directions for marking and replacing the timing belt very carefully because an incorrectly timed belt could be disastrous. One more thing, you should most likely replace the timing belt along with the water pump, because if not you'll have to replace it later which means doing this all over again, and that's not too much fun