hiya,
there should be some app to bridge the cam for use on mac, (if it's a usb cam) it's called iChatCamUSB [a bridge-ing app ] or something like that. Apparently it's still in beta stage and is a little buggy but lets you use a usb cam on mac, photobooth, ichat, imovie etc.
i use a firewire dv camera.. ;-) no need to get another piece of equipment.
cheers!

osxG