Lil' Viv,
go to your local AutoZone and look at Haynes Manual for your particular vehicle. See the section on replacing evaporator/heater core, it should be around that area. I changed mine (on '97 855 GLT) using Haynes Manual, as well as www.alldatadiy.com, which is an awesome site for do-it-yourselfer's. The most difficulty that I had (besides taking the whole dashboard apart, which is just plain tedious) was DISCONNECTING the old evaporator from the AC hoses in the engine compartment. You will need 2 Ford type spring clip tools to remove those lines (you can buy them at AutoZone for about 10 bucks for a set of 4). Would be nice if you had somebody to help you pulling and tagging. Maybe mine was just extra rusted or something, and you wouldn't have as much trouble, but that was what caused me the most difficulty. If you do decide to do it yourself, be sure to be VERY careful with airbag modules; also, in the process of taking the dashboard apart I would recommend that you bag and tag all the bolts that come off so that you would know exactly where they go. It would be very helpful if you took digital pictures (if you have a digital camera, that is) as you took your dashboard aside, because then you would be able to look at them and put it back together. Changing the evaporator (on my vehicle) wasn't limited to taking the dashboard apart, I alsa had to take the windshild wipers and windshield wiper motor out, so, in no question it is a big job. And it definately is worth about $1000. However, as long as I can save about $700 on labor, and the work doesn't include cylinders, engine, transmission, etc (something that one can really screw up), I will attempt to do it myself.

Anyway, hope this is helpful,

My $0.04

Max