Interesting more because of its price than its form factor, Ivyskin's new Zappak ($50) is a 3000mAh battery in a rectangular plastic and metal enclosure that sits just inside the footprint of an iPhone 3G or 3GS. The plastic houses a pop-out USB cable that can be used to recharge the battery, plus twin USB ports on the bottom that can be connected to self-supplied USB-to-iPod cables to recharge two devices at once. A set of red lights on the sideā¦