Hi! What kind of camcorder do you have? If it is a newer one with DV connectors I believe you will need a firewire 1394 card on your PC to capture the video off your camcorder. This is the digital way.
The analog way (and for older camcorders) is to use the video-out on your camcorder that you'd normally put into the video-in on your TV or VCR. You plug the video-out from the camcorder into a video-in on a capture card in your PC (such an an ATI All-In-Wonder capture board). You also connect the audio from the camcorder to the line-in on your computer's sound card.
The digital way gives you a higher quality source to manipulate on your PC.