I am not aware of a website that covers charging of AC systems for novices, however, the FSM is a good place to cover the details.
Of course, the FSM assumes you have the following:
1. Vacuum pump to evacuate the AC system of old refrigerant
2. Manifold to empty/fill the refrigerant from both the low and high pressure sides of the system.
If you lack these, you CAN do a "home brew" recharge, using one of those kits from WalMart, AutoZone, etc. They will work, if your system uses R134, which applies to a 1998 model. Those kits usually include some generic instructions on how to connect to the AC system and add the contents of the 12 oz. can of R134.
Be forewarned though, that if you just add R134 from a kit, and do not understand why the system was low to begin with, you may not fix the problem permanently.
Also, a word of warning--you can actually OVERFILL the AC system, and cause more damage than good. Thus, an AC manifold, with it's pressure guages, is useful in keeping this from happening.
Good luck.
