Yes, it is much like a home system. 1st you have to figure out what refrigerant you have and what the system should be charged at (there may be a spec plate on the compressor). If it is a newer car, it probably uses R134a. You can easily pick up cans of R134a at any autoparts store. The Hi-Lo ports should be either on the compressor or near the compressor. Typically, you just add to the system as needed.
If you have an older car, you can still recharge it, but the refrigerant is more expensive and harder to get. If you are an HVAC guy, it wouldn't be a problem besides the higher price. You could also convert the older system over to R134a. They do sell conversion kits for this. Ideally, you should evacuate the system to remove the old refrigerant and much of the oil. Replace the receiver/dryer. Replace with R134a and add the appropiate oil. The R134a doesn't cool quite as well, but most people I've talked to in hot climates said that it still did the trick.
If you don't already have one, search online for a Factory Service Manual (FSM) for your car. If you do any work on your car yourself, this is about the best tool you can have. This is what the dealerships use when troubleshooting your car and they contain all the specs, wiring diagrams, testing/installation procedures, etc.