Phone Aid is a reference application that gives you quick real information on what to do in case of a first aid emergency. It includes 5 different scenarios that include both picture instructions and audio instructions. The idea being that if you come across an emergency, you can start up this app, set it aside and follow the instructions in real-time from the audio.
In addition there is a great text reference for lesser emergencies -- like bee stings, etc.
Here's a demonstration video from the developer that gives you a good demonstration of what the app is like.
Phone Aid while not all encompassing is a great reference that I hope I will never have to use. Great safety app!