I just rebuilt the top of my motor the other day, and I have two pieces of advice:
1) Buy one of those heavy duty strap wrenches. Slip the loop over the crankshaft pulley, and have 1 person hold it tight with the use of a cheater bar. I used a hi-lift cheater bar, which I sliped over the end of the heavy duty strap wrench. It worked like a charm!
2) Go to Autozone and buy a Chrylser Harmonic Balancer Puller. This awesome tool allows you to grip onto the belt riding surface of the harmonic balancer, to pull the harmonic balancer off. This eliminates the need to use the treaded holes for pulling the balancer off. It cost me $70, but it was the quickest harmonic balancer removal job I'v ever done.

Good Luck!