Finally, here's the first iPhone battery extender that doesn't ruin the clean lines and refined design of your beloved bauble. The Mophie Juice Pack Air gives iPhone 3G an extra 270 hours of standby time, 4.5 hours of talk time, 4.5 hours of web browsing/emailing on 3G, and 5.4 hours using WiFi.
If you can wait until its Spring release, it'll cost you just shy of $80. That's a lot, but just look at it. It hardly adds any thickness at all to the iPhone, gives you the benefits of both a case and a battery extender without making your phone look dorky, and even has a quartet of LEDs indicating charge level.
It's about time! Now if Apple could just make an iPhone whose battery didn't fizzle in less than 3 hours, we wouldn't need such contrivances.