A couple days ago, ReadWriteWeb reported on a new Twitter hashtag syntax for people to use in emergencies, a syntax that would make it easier for computers to "automatically extract data about locations or the status of a road or person." For instance, a tweet requesting security at the General Hospital in Port-au-Prince might look something like this: "#haiti #need security #loc General Hospital PAP #contact @thehatian".
So what would be really cool (and I'm sure someone will do this before too long) would be to build a mobile web app that would, with a minimum of user input, build tweets for you using this syntax. The interface would contain only a handful of really large buttons, set against a very bright background (so the phone can double as a flashlight of course). The app could use the phone's GPS to geotag the tweet. Sending out a mobile S.O.S. would be as easy as pushing a two or three buttons.
On the other end, of course, fire, police and emergency medical departments could monitor these tweets using Twitter's search or some other Twitter search client (perhaps one that could plot these tweets realtime on a map). They would then be much better able to get help where it's needed the most. It's 911 for the 21st century!
I am continually amazed by the extent to which technology continues to improve our lives in so many ways.