GREAT IDEA!!!
To support my tractor habit- I happen to work in Emergency Medical Services full time, so I have some input on how to start something like this.
It is hard to start at the national level, but the local level is ideal to begin. Several options are available. In our area, the 2 organizations that would be a starting place are the local emergency planning commission.
Their role is to organize and catalog all available resources. As an example, our county has a complete listing of personell, resources and equipment available from EMS, Fire Service, Public works etc.
The second that comes to mind is the local community emergency response team (CERT). Volunteers organized to assist as needed at the local county or statewide level for a variety of needs.
The one thing to avoid is developing a "rougue program" and just showing up to help. Even though this is in the sense of volunteering, there have been too many examples of fly by night help showing up and "helping" for a fee. it would be difficult nowadays to just show up and not be turned around.
My brother, an Arborist actually registered as a business and contacted the better business bureau before going down to assist with Hurricane Katrina. This opened up a lot for him as municipalities would only source through channels that had verifiable information.
One last thought- The "Southern Baptist's" used to provide a lot of disaster relief (food/Shelter) mobile operations. If they still do this, maybe contacting them for guidance/suggestions/ offerring help might work as well.
let me know what you think!