Anker, the popular portable backup battery company, has released the Astro Mini, a lipstick-sized portable battery for iPhone. This battery packs 3000 mAh of battery capacity and can give your iPhone an additional 9 hours of talk time that can really save your ass when the power goes out.
The battery can charge just about any USB device, though Anker warns against using it with the iPad. However, I doubt this backup battery would do much to charge the iPad Air’s massive battery. You’d probably want something bigger if you’re looking to get some extra juice for your iPad.