[warwick]

I wrote an OS X app to do this sort of thing a few years ago. At the time, I just used MAC addresses of routers to determine location. I wish I could write it for the iPhone, but it's above and beyond what's allowed by the rules.

The holy grail for a laptop was switching your SMTP settings, since a lot of people use different ISPs at work and at home. That problem goes away with a phone, but ringer volume seems like a similar level issue for phones. I could also see doing things like reducing your notifications or changing your lock settings.

(If you're interested in my software, you can find it at http://codehackers.net/locations/)