I jsut did some of this for a different purpose. I had removed the radiator which made this somewhat easier. I then removed the fan shroud. I assume that if the radiator is not first removed, then the fan shroud is loosened and shoved toward the engine block. Then unbolt the fan blades. In my car, the bolts were not difficult to remove; I simply gently held the fan blades to prevent the whole assembly from spinning and turned out the bolts with a socket set. I then removed the serpentine belt. Since I was going to replace the belt anyway, I cut a chunk of the old belt to the circumferance of the fan pulley, wrapped this junk of belt around that pulley, and used a piece of electrician's tape to hold the belt ends together. I then used a vise grip like tool which uses a chain to wrap around the circular object you wich to control, and ran the chain of this tool around the fan pulley and clamped the tool lightly shut. The old piece of belt protected the pulley from the chain of the clamping tool and gave a rubber gripping action which increased the overall friction and effectiveness of the clamping tool. This was more than enough to hold the pulley in place while I used a rachet with an 8mm allen socket to loosen the bolt which holds the aluminum piece to the steel pulley. You don't need to remove the clip on front of the aluminum piece. Just pull the 8mm bolt and the aluminum piece slides off. I thought the process was pretty easy.
That said, I feel kind of dumb about not even knowing about that trick regarding using the piece of rod to lock the pulley in place. It's good to learn things!