The New Trent Travelpak NT400C ($44.95) is both an AC charger/adapter and an external 4000 mAh battery with two USB slots. What a great idea and a handy gadget to throw in your bag while on the road.
The external battery is powerful enough to fully charge an iPhone twice, according to NT400C specs. There is a power off/on switch and an OED indicator light that signals the power level remaining in the battery.
