New Trent Easypak 7000mAh Portable Triple USB Port External Battery Charger/Power Pack for Smartphones, Tablets and more (w/built-in USB cable)
This is a fantastic portable power supply. Sleek design and relatively small size. You have two USB charging ports one at 1 amp and one 2.1 amp. You can charge two devices at the same time. I bought it because I was using my iPod touch 4g a lot throughout the day and I wanted to be able to be able to keep using it while out and about as a school administrator. Thus most definitely fits the bill. I recently bought an iPhone and having this portable power has been fantastic!  Highly recommended