Hi,
If Using an External Camera the Mac has to have a suitable Driver for this.
If Firewire the camera needs straight forward DV output (Not HDV or MPEG or other format)
This is critical for iChat but less so for Photo Booth.
To "See" the camera in Photo Booth it has to be plugged in first before Photo Booth is started to display th picture in Photo Booth.
Other USB Cameras can be used if they are USB 2.0 And you have a USB 2.0 port and the camera is UVC Compliant (USB Video Class)
These tend to be marked either Vsta Certified or UVD compliant.
The OS has had a UVC driver since 10.4.9
USB 1.1 cameras are likely to need a Mac Driver that comes with the camera or be able to use one of two generic Drivers from either macam or IOXperts
(for iChat they need the
iSUSBCam Utility as well)
The IUSBCam page has a link to A Camear Guide page that links to the two generic drivers and tells you about which some cameras need (or come with them)
10:05 PM Friday; April 24, 2009