Here is a great idea that should have come into more common use a while back:
http://www.theregister.co.uk/2005/07/14/ice_mobile/
‘The idea is that you store the word “ICE” in your mobile phone address book, and against it enter the number of the person you would want to be contacted “In Case of Emergency”.’
I’ve already added my ICE and ICE1 numbers, though I hope they never have to be used. Another idea might be to keep a saved draft of a message you’d like sent to the ICE contact person. It would also be useful to have your name somewhere in the wallpaper, but not all phones support this.