Incase has announced that they will be releasing this new Powerslider case for the iPhone 3G that actually doubles as a power source, in addition to its most obvious function: protecting the device. It has a built in custom engineered lithium-ion polymer battery that is the first point of contact as far as power is concerned, and once that source is gone, it then begins to draw power from the iPhone’s battery and operates off of that. This will more than double the battery life of the iPhone. Sounds like a great product for those who use the phone heavily. Check the images after the jump.