Four sites that I want to highlight that are excellent sources of information about Katrina.
Earthlink has put up a site where you can search for someone or add information on how to reach someone. They also provide links to other sites that provide the same information.
Craigslist has put up a page with links to all the various relief organizations and information on how you can help.
Metroblogging New Orleans is covering the disaster from the local angle.
The Inderdictor is a LiveJournal user who looks after one of the few (maybe only) ISPs running in New Orleans (he’s on diesel power). Minute-by-Minute postings of the chaos on the streets.