Got this message from some fine folks at DHS:

"In responding to recent natural disasters and state of emergencies due to Hurricane Katrina, and now Rita, the DHS US-CERT in collaboration with the Control Systems Security Center (CSSC) has released a Hurricane Katrina Control System Assistance Informational Paper. The US CERT Control Systems Security Center (CSSC) has placed this informational bulletin here.  Please go to this site and click on the link under reports for "Hurricane Katrina Control Systems Assistance (PDF)."

This paper describes how to get physical and electronic operations back on-line in a time of crisis.