Isnt there an artical somewhere about making a USB led lite and shows u what wires to use and hooking up the resistor and all that...
yes, let me find it in a sec...But for now, the usb line carries 5v at 500ma, so just use a led calculator to bring down the voltage of the line to the led's specs. Very simple mod, just put an approproate resistor on the red 5v wire and connect the ground (black) and the 5v (red) to the appropriate leads on the LED.
You could try this one at Moddin.net, or this one at Pimprig.com that dosent seem to be working right now. Alex