[Ian]

no such thing as a freon tank. the big canister looking thing is the drier.

Anyway, just get all the refridgerant out of the system. I would recommend using a AC machine, but its really up to you. If its R12 in the lines, be careful, it isnt very good for you. R134a is a little less harsh, but still not good. Once you get the crap out of the lines and system, disconnect or cut the lines, unbolt the compressor and throw it in the garbage. I guess you want to get rid of the condenser too, to do that, you're gonna have to remove the radiator. not a huge deal, but it can get sort of messy.

You mentioned removing the heater core.....have fun. you have to take the dash out I believe. I never got around to doing mine when I had my GTA so i dont know exactly how long it will take. I doubt you will get everything done in one day, but I can see getting all the AC equipment out in a day.