CCH has a short piece laying out tax options available to disaster victims.
I would only add that the tax code will allow people to deduct losses they incurred in the hurricane. Unfortunately, there are limitations and only losses exceeding 10% of a persons gross income are deductible. On the good side, you can choose whether to wait and claim the losses on your 2005 tax return or file an amended 2004 return and go ahead and take the loss now. (The deductible loss will probably be less, but you'll get the money much quicker.)
However, deducting a loss means first knowing what the value of the lost property was. From what I'm hearing, the normal methods of establishing tax losses may be meaningless in New Orleans and some other areas. I suspect a special rule will be needed to help these people estimate their losses, but so far no such rule is forthcoming.