There's a new device out for emergencys and for letting people know where you are while in remote areas. It enables a 911 to be sent and your location pinpointed. It also allows you to let people know by email or text message on your cell phone your location and if you are OK. Works by satelite. Very cool and great for people hiking where there is no cell phone coverage in case of emergency. You need to get a subscription to the service in addition to buying the device. Available at REI also.
Info here:
http://www.findmespot.com/home.aspx