Here is a summary of the best resources available (list of resources maintained by Google at the GE Forums):

1. Subject: NOAA Overlays Network Link
   Link: NOAA Overlays Network Link
   Description: Based on your current view (you have to be zoomed in), shows Katrina damage imagery for the main areas
2. Subject: All NOAA Images (see this for details)
   Link: All NOAA Overlays
   Description:: Slow to load, and you have to click on each mark to open each image (large images), but most comprehensive collection of images and color coded according to date
3. Subject: Locations of Katrina Red Cross shelters
   Link: Katrina Red Cross shelters
   Description: partial list (598 of 766) of the existing Red Cross shelters, their capacity, occupancy, and status as of Sept. 12th
4. Subject: FEMA Damage Assessment 14 Sept. 2005
   Link: FEMA Damage Assessment 14 Sept. 200
   Description: Graphically shows damaged areas with color shaded regions. Includes flood coverage, damage areas by damage level, road/rail/bridge outages (Note: see this if you have graphics problems)
5. Subject: 23 FEMA Disaster Recovery Centers, Sept. 10
   Link: FEMA Disaster Recovery Centers
   Description: Location of FEBA Disaster Recovery Centers

Dozens of users of GE volunteered their time to help put together valuable images of Katrina damage, Red Cross Shelter locations, and help many people who lived in the area determine whether their homes were threatened, damaged, or destroyed. In addition, the GE development team themselves put in many hours (especially over the Labor Day Holiday weekend) to create customized databases, network links, and set up massive servers to meet the demands around the world. Goolge maintains announcements about this information at this forum.