Plaintalk Microphone and G4

[Adam Lippiatt]

Hello

I have an old plaintalk microphone and was wondering if anyone knew 
whether it worked on a mirror door G4?  It won't go into the microphone 
connector, but maybe the line in connector?

Alternatively, should I be thinking about a USB microphone and if so, 
does anyone have any recommendations?

Thanks

Adam Lippiatt