I have a mini DV camcorder that has USB but I can't seem to get it to transfer to my Macbook without using a windows app. Leopard/iMovie/QT doesn't recgonize it.
USB means MPEG-2. I don't think the old iMovie works with MPEG-2, or any of the other formats, yet.
To clarify, many miniDV camcorders have USB ports, but they are NOT meant for video. They are for accessing still images stored on the memory card. Many cameras are also capable of pretending to be a webcam, and this video stream can be captured over USB, but you are not getting the full resolution/quality of the miniDV format.
The hard-drive based camcorders do use USB to transfer MPEG2 (or whatever) encoded files. But not the miniDV camcorders.
I would love to give a new hard-drive-based HD camera a try, but I've been reading so many things about them being incompatible with iMovie/FCE that I'm still in wait-and-see mode.