The worst thing that can happen to a smartphone owner, even worse than seeing that you have no bars of service, is running out of power. Maybe you didn’t have time to top it up overnight or you don’t have a car charger. Whatever the case, with no power, you can’t really do anything.

There are already a variety of power-packing solutions for the iPhone on the market and now Case-Mate is joining the fray with the iPhone 3G Fuel, a rechargeable battery pack for the iPhone 3G that doubles as a protective case, albeit a rather bulky one.

With the 2300mAh battery pack, you get up to 9 additional hours of talk time, up to 7 hours of Internet, up to 8 hours of video, up to 24 hours of audio, or up to 250 additional hours of standby time. That should tie you over until the next real charging opportunity right?

On the flip side, Case-Mate is also launching a nearly identical product for the BlackBerry Bold, a protective holster-style case with a battery pack that is also known as the Fuel. Both battery packs feature simple slide-in/out access and retail for $79.99.