I'm Coming: Now They Know for Sure

The clever people who dream up smartphone apps have come up with a great one for the iPhone: I'm Coming. This app does one thing and does it well: It alerts friends, family, colleagues by email when you're reached a particular place so that they know you'll be arriving soon.

For instance, you could set I'm Coming to send an email to you spouse when you reach the Beltway during your drive back from New York City. Or you could set your kid's iPhone to let you know when the bus that's returning from the field trip is close to DC.  Brilliant.

And more brilliant apps are taking advantage of smartphones' built-in GPS. Sleep Blaster is another. Sleep blaster is an alarm clock app that wakes you up when you're reached a particular destination. No longer do you have to ask the person sitting next to you on the train, "Could you wake me when we get to Philly?"