ReVIVE Series TwinPort 5000mAh DUAL USB Universal Back-up Battery Pack with Rapid 2.1A Charging - Includes miniBOLT AC / DC USB Charger , MicroUSB and MiniUSB Charging Cables
I highly recommend this back-up charger especially for iPads, kindles, nooks, iPod touch, iPod nanos, etc. I ordered this product from Amazon.com and it was shipped to me in two days, December 23, 2011.  I wish I had known about this Charger earlier, I could have saved myself time and money. So go on and order this charger and you will be happy you did.