From Keith Stouffer at NIST:
Hurricane Katrina Control Center Assistance
US-CERT in collaboration with the Control Systems Security Center (CSSC) has released a Hurricane Katrina Control System Assistance Informational paper to provide owner/operators assistance in securely and safely restarting control systems following a major disaster such as Hurricane Katrina.
The document can be found at the following site:
Ought to be very informative reading after Hurricane Rita, too.