You can do the job yourself, but you need to take the car to a licensed A/C shop to have the system evacuated. Once the system is evacuated there is no worry of freon escaping. Then when done with the work, go back and get a recharge and oil.
I don't know if the shop would charge to evacuate your system, I have a friend who has the equipment, and he evacuates my systems for nothing. Can't say the same about the recharge though.
73 280 SEL 4.5
[This message has been edited by MikeTangas (edited 05-10-2000).]