wrote:

I don't know of an off-the-shelf adapter, but it needs to be an
impedance adapter. Headsets are typically 150-300 Ohm, with voltages
running upwards of 10V. Portable devices like cd players and other
line-in critters use a much lower voltage, and expect a lower source
impedance. If you truly want to go into the mic port, it'd have to accept
and modulate the bias voltage coming from the video-cam as well, I'd
expect.

If it were me, I'd build one... but need to do more research
first.

If you have a Sony with a mic in a simple cord from Radio Shack will
suffice.