last Month, I reviewed this mobile charger from Richardsolo.
http://www.iphonelife.com/blog/5811/review-richardsolo-9000-mah-mobile-charger
If you were planning on getting one, it's currently on sale until Monday. Here are the details from the email I received.
For this week only, save big on the powerful RichardSolo Mobile Charger! This 9000 mAh backup battery connects by USB cable included with your device for charging iPad, all iPhone/iPod models (except shuffle), smartphones, and more.