I am a teacher and am in charge of a student Mac lab. All of the computers are g5's, none have built-in cameras, but all should, as far as I understand, have built-in microphones. On some of the computers, the internal microphone works fine. On a few, it doesn't show up in the Sound, Input panel. All that shows up is "Line-In". I'm pretty sure that "Internal Microphone" should be an option. So why isn't it?
To clarify, "I take it these are really G5 iMacs you're talking about and not PoewrMac G5s, (Tower Model)?", yes, they are G5 iMacs, with the CPU and the monitor all in one idea.
So, apparently we have a mix-and-match assortment of G5's, most are original models, and some are the Ambient Light Sensor models (which are the only ones with built-in microphones). Thanks all for your prompt and helpful advice!