The mayor says there are most likely thousands dead:

The frightening estimate came as desperation deepened in the city, with gunfire crackling sporadically and looters by the hundreds roaming the streets and ransacking tiny shops and big-box stores alike with seeming impunity.

"We know there is a significant number of dead bodies in the water," and other people dead in attics, Mayor Ray Nagin said. Asked how many, he said: "Minimum, hundreds. Most likely, thousands."

On some of the few roads that were still open, people waved at passing cars with empty water jugs, begging for relief. Hundreds of people appeared to have spent the night on a crippled highway.

Meanwhile, there is a run on the gas stations. Tradermike also posted about it.