Exolife, a slick new battery case for the iPhone 4
Another cool feature is the battery meter on the back of the case, letting you know when you need to refresh the Exolife. The case is also fairly ergonomic, allowing access to the headphone jack, volume buttons, etc.
One potential complaint is that there is a pass-through miniUSB instead of a pass-through 30-pin connector (the iPhone/iPod standard). This means you'll have to remove the case in order to use it with traditional docking accessories. The Exolife also leaves the iPhone 4's screen raised above the case, making it vulnerable to flat drops.
The Exolife costs US$90, comes in both white and black, and can be purchased from the EXOGEAR website linked below.
source: EXOGEAR via GIZMODO