The upcoming OpenMoko phone (named 'Neo FreeRunner' or GTA02 architecture) is going to have an accelerometer. Someone started a thread about how one can make use of this new piece of hardware. So far there have been many replies on the thread and they have very innovative ideas.
My favorite one, a suggestion from Crane, Matthew:
... if the device:Check out the rest here.
- goes from 60km+ to 0 in short order, e.g. high g stop
- while traveling horizontally
- over a road
- an on-screen alert/countdown is not stopped
Then it's likely a vehicular accident so auto-call/sms for help with
some kind of countdown to disable. Only really possible to do that with
a phone + GPS + acell.