Energizer has created a silicone case with a built in rechargeable battery for iPhone 4. The case claims to extend your iPhone 4’s battery life by 200 hours of standby, five hours of 3G talktime and four hours of Wi-Fi/3G Internet usage. Obviously these types of cases add extra weight - the Energizer case adds 55 grams to the iPhone 4’s 137 grams. The AP1201 is on sale now in the US and priced at $69.99, but isn't available in Europe just yet!.
Soon I hope they will have one out for the IPod Touch 4G well here is a video of it in action. ( the charging case that is)
Energizer® AP1201 rechargeable case for the new iPhone® 4