ChargeCard is a Kickstarter project that has been funded and will help with you easily carry a charger for your iPhone.
Designed in the form of a credit card, the ChargeCard has a 30-pin connector on one end, a retractable USB port on the other end.
The device is priced at $ 25 and it is available for worldwide shipping.
For the new iPhone 5 version with Lightning connector you will have to wait until May 2013. It costs $ 25.
Via Cult of Mac