Some resources for locating those missing in the aftermath of Hurricane Katrina:

New Orleans chapter of National Association of Catering Executives bulletin board
National Next of Kin Registry
Salvation Army Health and Welfare Information Request Form
FEMA Disaster Assistance Process
NowPublic Missing Persons Board
Nola.com Missing Persons Board
Nola.com "I'm Okay" Board
Nola.com Homes Available Board
Nola.com Pet Rescue Board
WDSU-TV Safe/Missing Persons Boards (By Parish)
WWL-TV Missing Persons Forum
WWL-TV Post If You're Okay Board
Houma, La., Courier: Storm Forum
Sunherald (Miss.) Missing Persons Board
The Mississippi Press Missing Persons Forum
CNN.com Safe List
MSNBC "Looking For" List
Yahoo Hurricane Katrina Message Boards (Broken out by city)
Katrina Family and Friends Forum