Can you change batteries while on A/C without power down? This isn't something i'd try without knowing in advance. Some devices use the battery as a cap for a dumb charger...

It's also unlikely. I'd have to be out somewhere, with my extra battery, and my A/C, and be near an outlet, and be low on the first battery, and have at least one app up that doesn't remember where it was, and i'd have to care. Maybe if I flew more, and, uhm, watched movies. When my 16 GB SD arrives, maybe it'll be an option.

I used to wait 10-15 minutes near an outlet at the end of the day, and it was good enough to just plug in for that long. I didn't have a spare battery back then.