The best blogs I have found regarding New Orleans and Katrina so far are:

The Irish Trojan's blog - Brendan Loy's homepage

Brendan's blog has been amazing and the attention he's received is well-deserved. He had excellent coverage even before the hurricane hit, he taught me a lot about Hurricanes. I didn't know that Hurricanes have "eye replacement cycles" before I visited his site.

I think I found this site via Google doing some Hurricane searches on Saturday afternoon when I first heard Katrina was a threat to NOLA.

The people behind The Interdictor are an amazing story unto themselves. They are living in the datacenter they work at, in a 27 floor building IN NEW ORLEANS, because it's their job to keep the thing running. And they're taking that responsibility EXTREMELY seriously. They have a diesel generator powering the data center and at least part of their network backbone is still functioning. Amazing pictures and video there too. I pity any looter that makes the mistake of trying to mess with those guys.