Today I built isight-firmware-tools for ppc64 and added it to the 64-bits repository. Apple Built-in iSight requires firmware that can be extracted from the Mac OS X USBVideo driver. This package provides tools for extracting the firmware from the driver and installing udev rules and tools to automatically load the firmware when needed. I tested the program and it works. The isight.fw file will be put in /lib/firmware. My iSight camera in the G5 iMac works well in Cheese with this installed firmware.
For more information have a look at the Ubuntu wiki site.