I am trying to replace my AC compressor, but I was told I need to release the pressure and drain the freon before I do so. Is that correct, and if so how do I do it?

 

You will need to take it to a facility that has the capability of evacuating and capturing the freon. Once this is done you can take apart and repair your AC system. Then you would take it back to said facility where they can recharge your AC system.

 

You need to take your car to a shop and have them recover the refrigerant before you open the system if there is any refrigerant left in it. A lot of shops will do it for free since they make money off the refrigerant. If it has R12 freon in it you will probably get paid a decent amount of money to have a shop recover it. R12 is very valuable stuff.

 

I don't think it's a job that's worth doing yourself, take it to a garage. Just make sure you don't end up paying for a new set of wheels and a spoiler