It looks like a number of sites have updated their imagery. DigitalGlobe has perhaps the best images of New Orelans available anywhere, including an overview one of the downtown area and a more detailed one that includes the Superdome. As well, some detailed images of the levee breaks are also available. Earth Observatory has taken one of the images and provided some textual background to it.

Landsat has a couple of more before and after shots of parts of the Gulf coast. Unfortunately cloud cover obscures some of the details.

Orbimage also has a few new photos, including before and after shots of the Louis Armstrong International Airport and Tulane University. All these images are in black and white; nevertheless, they clearly show the extent of flooding. Included in the set is one image swath that covers an extensive part of the city.

Spot Image has an infrared satellite image of New Orelans on its site at 20 m resolution. Again, flooding is very visible on this image.