DJ Josef PrÅ¯Å¡a, the author of the iPhone/Arduino/MaxMSP/OSC hack from iPhone Hacks, just let me know about this great project he made from a spare MSI Wind battery; a nice and juicy battery pack for USB devices. He was originally looking for something to power his Monome 128, but it ended up being great for his iPhone as well. And the battery can still be used in the Wind, apparently. He uses a 7805 for this; it would be interesting to see another kind of voltage regulator in a future revision to this.
In the Maker Shed: