I believe there is already a volunteer emergency radio service set up using ham radios (ARES/ARRL).
There is some good background information on the Amateur Radio Emergency Service (ARES) here:
http://www.arrl.org/aresI've been registered with them for years, and they have training all around the country that is very informative. I haven't deployed, but have been on emergency nets from time to time during major snow storms and the occasional hurricane up here in the Northeast. There are other folks that are far more involved and dedicated to this, I just always wanted to be ready if we get "the big one" up in my area.
Like anything... getting your license doesn't accomplish much. It's training, and practice that make amateur radio actually useful in a time of crisis. Integrating with your local EMS folks, perhaps thru CERT, will also help. There are dedicated ham operators all over the country that participate in drills every month simulating how they would handle emergency traffic under various scenarios. We have a local Hospital Net that each month has local amateurs communicating with 3 major hospitals to provide comms should their primary communications fail.
A related service is the Skywarn service, where NOAA and amateurs combine to track local conditions:
http://skywarn.org/Great for sharing highly localized, detailed situation reports during and after major weather events so that resources can be deployed effectively.
Cheers - Ron (K1RON)