Power Support Japan has introduced its new Air Jacket Set for the iPhone 3G (Translated link). Like the company’s prior Air Jacket Sets for the original iPhone and iPod touch, the iPhone 3G set consists of an extremely thin polycarbonate rear plate, which is used in conjunction with one of the two included protective screen films (one clear, one anti-glare). The set also includes a Dock Connector protector and a dust-collection cleaning sheet. Currently available in clear for 2,280 yen (~$21), the Power Support Air Jacket Set for iPhone 3G will soon be available in black and white variations, as well. U.S. availability has not yet been announced.
Update: Power Support USA is now offering the Air Jacket for iPhone 3G in clear or black for $35.