We have talked a couple times now about the GSLO Volt solar charger case for the iPhone that will be offered by GSLO in the US. The company has announced that it has received its first shipment of demo cases from the manufacturer for testing.
According to GSLO this is the last step before it can start marketing the cases and selling them in the US. GSLO is going to "thoroughly test" Volt units to ensure that the cases are manufactured well before selling them.
The Volt is a case with a battery packs that has a small solar panel on the back. The idea is that the solar panel will trickle charge the cases internal battery and help keep it charged up longer. The Volt is also the only battery pack I have heard of that will work with the iPhone 3GS and iPhone 4. You can reserve your own Volt case here.