5v regulator (Lm7805)
Female USB port
Braided wire (20g)
Used 9v battery (Walgreen's brand)
5 minute liquid epoxy
Non-conductive epoxy putty
The circuit design is from http://ipod.hackaday.com/entry/1234000270029372/
All I did was add an LED so I could see if the battery was good. He's got nice diagrams of the USB and regulator to help you wire this together.