A Harbor Freight chain wrench (looks like a vise grip but with a loop of chain instead of jaws) will also do an excellent job - cut up an old belt and wrap the pulley to protect it before looping the chain around it. Use a pipe over one of the handles to increase leverage on the wrench and have an assistant (with breaker bar and lots of leverage) loosen the pulley nut. Or, wedge the chain wrench/bar against the ground/frame and loosen it yourself.

I have removed pulleys from 3 different vehicles using this tool and it has worked well.

1988 Isuzu Trooper LS
2.8l Isuzu 4JB1-TC intercooled turbo diesel
www.dieseltrooper.blogspot.com