Update: Proceed with caution, Amazon users rate it very low.
1SaleaDay has a new Mini Mobile 1000mAh 30-pin battery for $4.99. Add another $4.99 for Shipping on this portable iOS/iPod device life extender…
This compact external battery can keep your iPhone or iPad charged anytime, anywhere. Get an extra 3 hours of talk time on your iPhone, 30 hours of music playback on your iPad, and 6 hours of video playback on your iPod nano! Lightweight and easy to carry around, it’s the strongest clip-on iPod/iPhone battery with absolutely no cables – it’s even small enough to leave it connected all day! Plus, you can charge your device and the battery pack at the same time.