Quoting from the ZAP press release, "Electric car pioneer ZAP says its iZAP battery designed for the iPod is more useful for the energy intensive iPhone."
According to ZAP CEO Steve Schneider, "...if an iPod runs out of power, losing your music and video is not as critical to your business trip as the iPhone. You lose your cell phone access, text messages, Internet and email access, time zone clock, business notes, scheduling software, driving maps, calculator and all the other news and information for which the iPhone was designed."
Does the battery life for the Apple iPhone really need a helping hand? The iPhoneWriter.com web site is wrapping up it's own real-world Apple iPhone battery life test. The final results and blog entry are forthcoming, but preliminary findings indicate that the Apple iPhone has superb battery life in real-world usage conditions. Is $79 and toting around an extra device worth it or necessary?
Another question is whether or not people want to carry around an extra, external device that will ultimately detract from the functionality and sleek design that the Apple iPhone provides. You shouldn't need test results to answer this question!