Double the Battery Life of your iPhone

Maybe one of the only concerns about the iPhone is its not-easily replaceable battery, even though most users of mobile phones will never replace the battery of their handheld.
If some systems are already available for extending the battery life of the iPhone Morphie offers an elegant alternative:

The Juice Pack is an iPhone clip-holder designed to be attached to your belt, it includes a Li-Po battery which will double the original battery life. Featuring an iPod port this holder can be charged simultaneously with the iPhone. It is available around 100 USD.
Let's hope that the Juice Pack is able to accommodate the iPhone 3G as Apple modified the design enough to make several iPhone 1G-dedicated peripheral not compatible with the new 3G model.