Wired News has an article with lots of links relating to Katrina.
With most of New Orleans underwater, certain online resources have emerged as crucial access points for news, housing information and live community updates. Wired News has compiled a list of some of the best.
They have a second article about how Craiglist is providing help.
In relief efforts, too, the internet is proving invaluable, as websites have become hubs for putting badly needed goods and services directly into the hands of people who need them most. Where organizations like the Red Cross discourage anything other than financial donations, sites like craigslist allow people to meet up with victims for face-to-face aid. Craigslist users have flooded the New Orleans site with offers of shelter and comfort.