Mophie Juice Pack Pro, Military Grade Protection for the iPhone
"Staying true to its peripheral nature, Mophie's outed yet another iPhone companion: the Juice Pack PRO."
Very spendy at $130.00 USD, but it does offer Military Grade protection from the elements. It doesn't offer as much time as other battery packs but it will at least double what you have with a regular iPhone.
iPhone 4, 1.6 GHz Core 2 Duo MacBook Air, Apple TV, 2.66GHz Intel C2D Mac Mini, 1TB TC, Airport Extreme,several iPods and an iPad, 32GB Wi-Fi version. Follow me