Battery life for the iPhone, especially for those who use Wi-Fi a lot and 3G, could - to say the least - be better. Thankfully, there's now some help to keep your Apple smartphone up and running longer. The Mophie Juice Pack, already available for the original iPhone, will soon ship for the iPhone 3G as well.

` This peripheral is a sled that houses a rechargeable lithium polymer battery within an ergonomic, comfort-grip case with a soft-touch, non-slip finish. Sure, it adds a bit of bulk to the iPhone, but I believe most would be willing to lose a little sleekness every once in a while for far better battery life, especially when an outlet isn't in sight.

What exactly does the Juice Pack deliver? It is supposed to provide up to 350 hours of additional standby time, 6 hours of talk time on 3G (12 hours on 2G), 6 hours of Internet use on 3G (7 hours on Wi-Fi), 28 hours of audio playpack and 8 hours of video playback.

The iPhone 3G Juice Pack goes for $99.95. You can pre-order it now. And it will start shipping on October 30th. See here to learn more.