Banger
It's unlikely you'll need a USB cable. Most digital camcorders transfer digital video data to the computer via a 'Firewire' connection. This is a high speed serial connection similar to USB... but different! Below, I have shown typical Firewire connectors - as you can see, they look somewhat like USB, but they are NOT interchangeable!
Video editing is probably the most demanding task most computers will ever face. There's a good intro article
here. If you DO want to edit video, you'll need a fairly modern computer with a fast processor, a fair amount of RAM and (importantly) a big hard drive. Preferably, the video should be saved on a different drive from where you have Windaz installed. Check your computer for a socket labelled 'Firewire', 'iLink', or '1394'. If you have one, you'll just need the cable (try
eBuyer. If not, you will indeed need an internal Firewire card. There are cheap ones available (under £9), but you might be better off buying a decent make such as Belkin. Again, mail order will be quite a bit cheaper than local retail (around £23 for the card, £3.50 for the cable - Quickcode 77160 on eBuyer).
Need any more info, send me a PM.