Before you run out to buy a microphone, do some homework about your camcorder. What type of connector does the external mic jack use? Most likely it’s a 1?8-inch mini. Is it mono or stereo? This is just as important as the connector size. Connecting a mono plug into a stereo jack will give you problems.
Your camcorder may have a hot-shoe (similar to an external flash attachment on a still camera) that allows you to mount an external microphone onto the camcorder.
The hot-shoe also has electrical contacts to pass audio from the mic to the camcorder. Unfortunately, there’s no universal standard for this accessory shoe, so verify that the external microphone will work with your specific camera.
While I usually joke that the audio is the squeaky part of the picture, in reality, it can be just as important as the moving image. TV stations know that they’re less likely to lose viewers if they have “technical difficulties” involving loss of picture with the sound intact, than if they lose the sound but not the picture. While your audience may be captive, they’ll appreciate your attention to the sound in your movies.