The earliest versions I know, back when versions 8 and 9 were out, they had two versions of the Moviebox device. There was Moviebox DV and Moviebox USB. Moviebox DV allowed capture of composite and S-video and DV. It connected to the computer via a Firewire port.
Moviebox USB was nearly the same, except it didn't have the DV/Firewire ports on it, and it connected via USB port.
In 2004, when Pinnacle Systems introduced Pinnacle Studio Plus 9, they came up with a newer, deluxe version of the Moviebox. It was a lot like Moviebox DV, complete with the Firewire port, except that it connected to the computer via USB-2.0.
In 2005, Pinnacle released Studio 10, and had two different Moviebox-style packages. The version that came with the regular version of Pinnacle Studio 10.0, it included a basic USB device that featured analog-in ports for composite and S-video (but no analog-out ports), as well as a Firewire in/out port on the device in the back. It was called Pinnacle USB-500.
The USB device that came with Pinnacle Studio Plus 10.0 was the 700-USB, and it was basically a re-labeling of the Moviebox Deluxe device from 2004.
Last year, when 10.5 became available for purchase, they released the current Moviebox and Moviebox Plus devices that are still available today, both USB-powered.