Originally Posted by Gilly

OK, there is the outside of the pulley, the part the belt spins, and the inside of the clutch, the part that rotates the compressor when the clutch is engaged. You just need to hold the inside part of the clutch and I believe you'll see a nut in the center which is removed to take off the clutch and pulley assembly, so no need to take off lines and can be done on the car. Not sure what's used to keep the inside of the clutch from rotating, I believe that nut is pretty low-torque, may be able to hold it by hand.
Gilly