I have checked this out and it is not an internet hoax like many other stuff like it. Don't believe the rubbish about it being a virus neither.

The East Anglian Ambulance service started of an idea about entering a specific phonebook entry into your mobile phone and calling it ICE (In case of emergency) and using a number for your next of kin or someone you would like contacting first should anything happen.

ICE - Mobile Phone Entry

Seems like a good idea to me. Especially given the times we are in.

The only pain I found is that if the ICE number is the same as another phonebook entry, the phone may just end up displaying that number instead of the usual expected name. So what I did was just to put (ICE) after the name and just have the one number saved.