For the DiYers out there, check out the Adafruit. They have a kit for a mint-tin sized double AA battery phone recharger(can use regular or rechargeable AA batteries).
http://adafruit.com/category/10

I decided to go all out and got a nice Li-poly battery, solar charger circuit and a solar panel and am putting together something like these pics:http://www.adafruit.com/products/390

It has been working great! I have had trouble with the N9 not recognizing some USB chargers in the past so make sure what you buy can be returned.