I just bought a Gomadic AA iPhone 3G Backup battery through Amazon to use as a backup for the bus journey to Tignes for the Varsity Ski Trip in a few weeks time. This was bought as a replacement for a similar, if easier to mount, Belkin AA backup I have had since My iPod 3rd Gen but which doesn’t work with the iPhone since 3G or iPod touch since version 2. I assume Apple have changed the pins it uses to charge or something. As the photo shows it makes the iPhone (in this case a 3GS) think that it is connected to the mains although not having had chance to test it I am not sure how long it can power the phone for on a set of batteries (It takes 4xAA), or whether it is able to resurrect a totally discharged phone. Hopefully it works or I will have a decidedly quiet long coach journey…