Apparantly this idea came from a British paramedic.
These days pretty much everyone has a mobile phone in their pocket.
Paramedics search through them when there's been an accident looking for relatives etc.
i.e. someone to contact that may know medical history and so on.
A frustrated British paramedic came up with the idea that everyone should enter important numbers under the name ICE in their phonebooks. This way paramedics can find the right number quickly.
This is spreading fast!! It's an excellent idea!!
Personally I've entered ICE followed by name to a few close ones.