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.