Here are some that I have found since:
The Hurricane-related information for health care professionals page from the CDC at http://www.bt.cdc.gov/disasters/hurricanes/hcp.asp
An interesting site which did make it to the column is the Eye of the Storm blog, at http://dancingwithkatrina.blogspot.com/, which is still being updated and has many photos. The bloggers are based in Mississippi. Another blog which I only just found is Hurricane Katrina, at http://hkatrina911.blogspot.com/, authored by journalism students at California State University, Long Beach.
The NLM has a page of links to health, toxicology and environmental health information at http://sis.nlm.nih.gov/enviro/hurricane.html.
The 13th October issue of the New England Journal of Medicine includes several eyewitness pieces about the aftermath of Katrina. These are available online free of charge, at http://content.nejm.org/content/vol353/issue15/index.shtml
CMAJ has published a short piece on the psychological aftermath of Katrina, at http://www.cmaj.ca/cgi/content/full/173/8/857?etoc and Student BMJ reports on the effects on medical students in the region at http://www.studentbmj.com/issues/05/10/news/356.php.
MSNBC is reporting that two New Orleans hospitals are beyond repair and will need to be demolished.