I have tried to do this as well, and I have only found instructions for Windows. I'm not sure if there is a way for Mac, and if there is, you wouldn't be able to use it with iChat because iChat needs a firewire camera. I actually use my camcorder plugged in with firewire as a webcam. Maybe you could hack the Mac to work with the EyeToy and hack iChat to use it, but I'm not sure.
Is there such a thing as an USB to FireWire converter??? can u technically create one by cutting on side of a USB cable and sutting a FireWire head out and rewiring it to create a converter???