http://www.nickstech.com/rc/lithium/

This site tells you everything about that packs, including where to get them. You tear them out of the cell phone packs, and just use the cells. This page tells you how to do all that. I did mine a little different. Mine are built long like a hotdog, and I didn't need to modify the moth. Oh, and this site has a link for the batteries at $4.00 a pack. Of course, you still need the charger unless you have one capable of doing lithium. I bought mine from Mark Hackett at the All Electronics site.