Eton has used its solar power expertise to create an iPhone case with a solar panel. This case they’ve called Mobius will double your iPhone’s battery life with its built in battery but it will also help power up your phone when you expose it to sunlight.
I can see this product being useful to those who are going hiking or camping and will be away from any electricity. You might not be able to get a signal to make a call or go online, but you can use useful apps that don’t require an internet connection like the compass or the flash to provide you light at night.
At the moment I’m writing this the item is still “coming soon” so we’ll see some more product specs, additional pictures and reviews once it becomes available to the public. Here is a link to the product page. For now enjoy these images of the Eton Mobius solar charging case for the iPhone 4.