Hi. Try this link for information:
http://www.arvc.org It is a national campground owners association. The main page will have a link on it (somewhere) that will take you to the "status of campgrounds in MS, LA and AL". Click that link and check the results.
As a campground owner, I have been keeping tabs on the situation (we are on the "willing to help list") and have been informed by other campground owners and some of our campers that FEMA has leased entire campgrounds in the south for a 3-6 month period.
I have also been informed by campers that there is an occasional campsite available, but if it is within an area that contains a large amount of evacuees in FEMA trailers, it is not a safe place to be.
I am sure this is not the case at all available camp areas. I am just relaying information from some of the campers that experienced these conditions.