Apple has shifted the design of their interface from 12V charging (firewire) to 5V charging (USB.) The iPhone originally used 12V firewire for charging...as did older iPods and Shuffles...They shifted to 5V charging in the last year. Which means devices which used to charge older iPhones, iPods, Shuffles can no longer charger newer devices.
To remedy this, you can purchase a new cable:
http://e-partssales.com/Merchant2/me...9972electronic
or, an interface adapter: