I have the iPhone 4 and absolutely love it. I was wondering if anyone had a good recommendation for interesting/fun/productive uses for a secondary iPhone, as I have some classmates who are upgrading from iPhone 3G and iPhone 3GS handsets to the iPhone 4, and have offered to sell me their old model for cheap. So far here is what I've come up with. Throw in your own ideas and let's make a good topic out of this! • Use it as an across-the-room alarm clock so that I can't actually hit snooze. • Leave it in my car to track it if it's ever stolen (I have MobileMe), occasionally charging it with a car charger. • Keep it in my photographer bag with a GPS coordinate logging app so that I can geotag my photos (do you need a data plan for this, or will this work anywhere?). • Plug it into a power outlet, connect it to my home wifi, and buy an app that will let me remotely check out the video feed on-demand from my primary iPhone (or a public computer) at any time. There could also be push notifications sent if it detects major movement. Is there such an app? • Use it with the Air Display app as a touch-sensitive palette chooser with graphics applications. Please comment on my ideas (tell me why a certain idea wouldn't work, what apps I would need to buy, et cetera) and suggest your own! Finally, a quick question: could an iPhone be used with an AT&T pay-as-you-go plan? This would be a great way to ensure that my international friends could be in touch with anyone they want when they visit the country for short vacations, without worry about paying roaming fees or unlocking their phones.