There were only a few thousand made before they switched to the intel chip, and I was wondering how rare it is and how much it is worth?

I have one, but it's close to worthless as a day-to-day machine because the capacitors on the GPU expanded and ultimately exploded. I can and do run it as a server for my website, IRC server, and sometimes radio station.
It has a 1.9GHz processor, upgraded to 2.5GB RAM, ATI Radeon X600 Pro GPU (busted). This is the model that has the ports on the back going horizontal rather than vertical, as I've seen on a few iMacs.