It's pretty much like this:

1.) Liquid fluid turns to vapor state. This heat transfer cools the air since the energy is being transferred to the fluid.
2.) Compressor/condensor compresses vaporized stuff back into liquid state. The heat is released and the fluid does it's thing again. (go back to step 1)

I'm no engineer or scientist so those who are can clarify or correct my words but that's basically it.

Easy as pie. :oh:

Here is a/c in a nut shell:

Refrigerent is compressed from compressor to condensor as a hot gas. Condensor condenses the hot gas to hot liquid and then gives off heat. Refrigerent runs through a metering device in liquid form and in the process evaporates to become a cold, vapor.

4 basic parts of an a/c system

1. compressor
2. condensor
3. metering device
4. evaporator

compressor acts like a "pump"

condensor acts like a "radiator"

metering device is a valve with a small orffice that only lets a small amount of liquid through to cool the liquid and changes form into gas or vapor

evaporator absorbs heat from the gas to give off an even cooler air

STAY AWAY!!!! ;)