For those of you interested (and yes, it may be too soon) - in reviewing who knew what when - from the Times Picayune perspective, I encourage you to re-read their blog - from Friday the 26th forward.
http://www.nola.com/newslogs/breakingtp/index.ssf?/mtlogs/nola_Times-Picayune/archives/2005_08.html (Thru August 31)
http://www.nola.com/newslogs/breakingtp/index.ssf?/mtlogs/nola_Times-Picayune/archives/2005_09.html (Beginning Sept. 1)
If you start at the bottom and re-read, you'll find many answers to those questions that have troubled at least some of us ... e.g. Why didn't Nagin try to use the busses to evacuate people w/o cars before the hurricane hit (well - he DID); When did they have the first signs of flooding (early Monday morning); Who said what when in press conferences (tons of interesting stuff there)
Anyway - just a suggestion. It takes a while. But it's the best, most comprehensive "fact-based" timeline-recounting we have.