SOS Panic is a free and small app witch will alert people or contacts that you are in an emergency and in need of assistance, it will send sms's to all the contacts that you specified as well as your GPS current location if you have a Gps enabled device. You can also setup a custom emergency sms text that will be included in the alert message.
Cannot stop the sound when the alarm turns on. I had to basically switch off the app all together.