Idler pulley broke off 1997 GP

The idler pulley broke off my son's 97 GP this morning. He's home, I'm at work, I have a few questions.

PIC:
http://i5.photobucket.com/albums/y183/guitarfish/Other/Pully1.jpg

The bolt is reverse threaded, right?
How do you get it off if the shaft spins?

Anything else I should know?

Thanks

Thats the third thread in 2 days that someone has lost/broke an idler pulley on a GP. THats going to be a pain to get off w/ the pulley broke..

Lock grip pliers? That's all I can think of.

I picked up a new pulley - the pulley has a bearing in it. It doesn't appear there's any need to hold the old one still to remove it. The bolt should come right out easily. Will report back tonight.

The repair is done. The bolt on the tensioner/idler comes off (reverse thread) easily. Remove old, slide on new, tighten. Voila.