All of the devices on which I've seen an auto-timezone feature have some sort of phone-system connection to a tower that knows what time zone it's in, and it hands that information back to the client device. I'm trying to envision how, if I were one of the developers, I would program a wifi-only device to make such a change automatically. Maybe something like a GeoIP interface, although we've all seen wild inaccuracies in that concept, sometimes on the order of two or three time zones, which is way less accuracy than I'd want for any task that I'd be automating. I can't come up with anything offhand that's any better than my work laptop, on which I have to set the timezone by hand once I arrive at my destination. Other thoughts?