Wendyl
I think you are confused about what firewire and USB are designed for.
Firewire or as Sony call it i-link and sometimes called IEEE 1394 is the interface designed to carry digital video signals. It beats USB hands down for connection of video camcorders for speed of transfer. Think of it as a high speed motorway compared to a gridlocked high street. Firewire 400�3200 Mbit/s, USB 12 or 480 Mbit/s
http://en.wikipedia.org/wiki/Firewire
USB was originally designed for i/o devices (mouse keyboard printers etc) and with the advent of USB 2.0 higher speed data transfer for external HDDs. It's still not as fast as Firewire though.
http://en.wikipedia.org/wiki/USB
You want a firewire lead.
The 4 pin (smaller one ) goes in the camcorder and the 6 pin (larger one ) goes in the computer
http://www.microdirect.co.uk/(12830)5M-4-Pin-t o-6-Pin-Firewire-Cable-USB145.aspx