I can't help much, but I understand your dilema. I used to have a Sony MiniDV camcorder, and faced this same situation. In my case, the camcorder came with software + drivers that recognized the camcorder when plugged in via Firewire or USB. Then the software allowed you to control the camcorder and import the video. It was a SLOW process, capturing video at normal playback speed. But it did work. Every camcorder except the new hard-drive based ones require that you re-encode your video from the tape to a digital format (MPG, AVI, etc). Once imported, you could edit the video and make smaller ones for the internet, burn a DVD, etc.
Anyway, check to see if your JVC camcorder came with software. I bet it will have the appropriate control program for offloading the video to your PC.
Good luck!
