Jeff’s got a smart post about the value of netizens planning ahead to coordinate around the next disaster, especially around peoplefinder and identity standards–see People Finder Format, the Katrina PeopleFinder Project (and more on the same)– that can look across various databases and other data sets.
Jeff’s ideas are good, but on a simpler level, I think the best thing to develop is a centralized wiki where people who want to address a problem can go–and everyone *knows* it’s a clearinghouse so the spontaneous respondents to a disaster have a designated resource to work from in addition to what happens on the fly.