Check out the Kensington Pocket Battery for Smartphones

[minus5252]

I just picked up one of the Kensington Pocket Battery for Smartphones from Amazon for around $12. It is a great device for emergencies, and can even be held with the phone while you are talking on it if need be. Here's a video review:http://www.youtube.com/watch?v=-DSwXpkcf88

Minus

 

[DrakonVolk]

Unfortunately, it's white, but even smaller than the Kensington and doubles as a wall charger/USB sync cable. Nifty little thing. Cost me 35.00 at Walmart.