I had a quick look in the workshop manual (Section B6 Page 3) and it doesn't seem to be that bad of a job (all things considered) the water pump is one of the higher up engine accessories so should be easier to access than the alternator or a/c for example. It does recommend raising the engine a few mm to give more clearance. There are 4 bolts on the pulley and another 4 bolts and 2 nuts on the pump itself.
