In reply to Ross.Cooper:
If you park in the coach car park it might just cost you more than you bargained for! The best parking set ups are on the left before you get to the municipal multistorey one. The one I've always used is Schaller. Their deal is that if you take their taxi up to Zermatt then the parking is free - even if you're there for a week. Their taxi is cheaper than the train by a few francs but sometimes you have to wait a few minutes for it to fill up. Ditto for coming back down. They are a bit cowboyish but they're cheap.