The Fire Department app connects those trained in CPR with those who need it, much like your colleagues who've put their hands up to be the building's first-aid volunteers. Using the iPhone's GPS, it alerts trained users of nearby casualties.
Once you elect to be tracked by the app, you basically sign over your permission to be notified when a reported emergency is near you. The app knows of said emergency because it intercepts data from 911 calls, figuring that a passerby trained in CPR is more likely to be of assistance than an ambulance miles away.
Users are alerted by a push notification, which will also inform you if there are any defibrillators nearby. It's one of those apps which makes a lot of sense, and actually makes you realize just how far advanced technology—and community—has come. [iTunes via TechCrunch]