Ahhh, you mean an analog input device with the standard RCA hookups?
I'm not very familiar with them, I do have one that came with my video card, which has it's own unique input interface on the card, so I don't know what interface they use, but it probably is USB 1.1/2.0.
They will have much lower quality, when transfering video via an analog source it loses a lot of its quality, which is why firewire is now ideal and found in practically all digital video cameras today, due to the fact that it transfers video without any loss of quality.
It's pretty much something you can't avoid unfortunetely.