yeah, isight is really finicky. i had problems getting isight-firmware-tools to function on my late 2007 macbook as well. the instructions here ( https://help.ubuntu.com/community/MactelSupportTeam/AppleiSight?action=show&redirect=AppleiSight ) 'should' do the trick. also, remember that, when reinstalling isight-firmware-tools to try again, you have to purge it first or the dialogue asking where to find the firmware will not reappear.
like i said, this 'should' work, but it didn't for me until i installed xubuntu on top of my ubuntu 10.10 install and booted it once or twice. i have no idea what was going on there