Here is a site of aerial photos of hurricane devastation on the Mississippi coast.
Here are more photos.
(HT to Instapundit)
Photos from NOLA, the Times-Picayune online site.
Photos from AL.com, a site of Alabama newspapers.
Photos from NOAA. These are satellite photos.
Flickr has over 10K photos of Katrina's devastation.
Weather.com has photos, too.