I'm pretty sure you mean the DCR-HC20?
Here is one review of it
here.
It has a
teeny single CCD, at 1/6th inch.
Here is a very basic look at
microphones. It briefly describes two external mics you might be talking about.
Most consumer-grade camcorders have a 1/8th inch jack input for Ext. Mic. Some mics will have an 1/4 inch plug, but a $3 part from Radio Shack can step it down, if you need to get it into your camera.