Right you are - sorry about that!
These are hand-held mics (similar to a cb microphone used on mounted units on trucks etc except without a speaker), and they have a switch on them that is depressed to activate the mic. There is no way of running another wire to the switch on the mic, which would be the ideal way to do it. I was hoping I would be able to detect somehow the AC signal that the voice generates. I want to light an LED when the mic is in use. If it flickers on an off between words etc, that is fine (well a delay would fix that, actually 
)
Hopefully, that is enough information? Let me know if its not.
Thanks!