AroundMe

One of the earliest -- and still best -- locator apps for iOS, AroundMe, makes it a snap to find all kinds of businesses and services near you. Among them: banks, gas stations, pharmacies, and hospitals. Just tap the category you want, then choose an entry to see its location on a map, get a route, or call it directly. There's also a map view that shows all the locations relative to where you are.

AroundMe is handy not just in an emergency, but also for non-emergency situations, like finding the nearest watering hole or ice-cream shop. It's one app I'd describe as indispensable.