Firewire is a high speed connection needed for the transfer of the massive quantity of data from a camcorder file.
The cable is different to the USB cable but only costs a few pounds.
Personally I dislike XP so can't advise on Moviemaker. I open Pinnacle Studio 8, go to the capture screen, select the capture device (camcorder) and hit the record button.
This operation will transfer an AVI file onto your PC ......... what do you plan to do with it then?