Katrina Timeline
The always useful Factcheck.org site has a well-sourced timeline of pre- and post-Katrina rescue efforts and related events.
While you are there, they also have what strikes me as a pretty fair roundup on Administration justifications for the Iraq war, and make the useful distinction between being wrong and outright lying. Of course, being consistently wrong on intelligence matters is still a fair basis for criticism, but getting of this distinction right is useful for moving discourse along more productively.