Over the holidays I tried out several external battery packs for the iPhone. One of my more favorite ones is the Powermonkey Discovery. Made by Powertraveler, the Powermonkey Discovery is a slim and light battery pack weighing a slight 107 grams and just 46 x 13 x 114mm in size. Inside you'll find a 3500mAh lithium-polymer battery. The battery is enough to charge an iPhone two times when the Powermonkey is fully juiced.
The external casing of the Powermonkey is what really (ahem) shines, though. It's made of a polished aluminum that almost looks like a silver bar you'd find on a pirate ship. The unit has six LED lights at the top. When all are lit green, the Powermonkey is full charged. When the last light is lit red, it's time to charge up the Powermonkey again. Like similar battery packs, you charge the Powermonkey by simply plugging it into your computer's USB port.
The Powermonkey Discovery I tested comes with the unit itself, one USB connection cable, and a travel pouch. It also comes with a standard dock cable and five additional adapter tips for Blackberry, HTC, Nokia, Sony Ericsson, Samsung, LG and Motorola devices as well as mini- and micro-USB cables. The adapters are a nice touch as you could charge multiple devices (including PSPs) from a single battery pack.
The Powermonkey Discovery is UK£45 (about US$72).