I don't know if you want to tackle this job by yourself. There's alot of things that need to be taken off the front of the engine to get access to the timing belt, including the main pulley. The nut for the main pulley is a real bii-otch to get off ! While your in there, you should change the water pump and replace the timing belt tensioner. I seem to recall there being a write up on doing it, on the 4X4Wire board.

If you have a mechanic you trust, I'd recommend letting them do this job. It'll save you some busted knuckles and alot of frustration. Of course, it'll also cost you. I ended up paying $600 to get the job done, split about 50/50, between parts and labor. The cost of the actual timing belt ends up being the cheapest part.