Federal Government
U.S. Department of Homeland Security
FEMA (Federal Emergency Mgmt Administration)
  IS-700 (NIMS on-line Course)
The White House
Defend America - Defense Dept. Anti-Terrorism News
Defense Threat Reduction Agency DoD

US Dept of Justice, Office for Domestic Preparedness
National Infrastructure Protection Center (FBI)
US Army's Soldier & Biological Chemical Command
 

Non-Governmental
The Center for State Homeland Security
The Homeland Defense Journal
National Emergency Number Association