I'm not sure that you can move tape footage via USB...
In the past I used Pinnacle's included USB importer, which converter analog to digital, but that gave no camera control. And quality was bad! Generally with digital video you're going to want to go with Firewire. It's fast, used in just about all new computers now, and a PCI Firewire card is $20 now.
I did some quick Google research, and it seems that Hi8 and Digital8 are really the only formats that would support USB transfer...everyone else uses Firewire because it's lots easier. Most if not all cameras with miniDV and higher formats will only support Firewire. Hope this is helpful!