For those staying in New Orleans
I say, use these people as part of the recovery effort. Give them the option of staying if and only if they agree on helping the rescue crew, or any other recovery crew for that matter. The Red Cross has just announced the need for 40 000 volunteers, so help is needed.
Furthermore, I suggest gathering all the able who were stranded by the hurricane without a home and a job, and offering them pay in return for help in rebuilding the city. In other words, give people the opportunity to earn a living rebuilding their city.