CBS News Disaster Links
One of the most comprehensive site I've seen. Links to every conceivable site that is authoritative and related to the topic. The variety may overwhelm you.

Disaster Center
Like the CBS site, this provides a one-stop overview of the current situation, worldwide. The site is very graphic and (in the fashion of Bloomberg TV) provides "at a glance" continuously updated information.

Emergency Medicine
Authoritative, comprehensive, etc.

Emergency Preparedness Dude - Very practical disaster prep and recovery information. I especially like his "Your Water Needs" calculator. Site is oriented toward natural disasters.

FEMA Library

Military operational equipment and survival clothing
The largest manufacturer and retail distributor of military survival and operational clothing and equipment in Great Britain, with 6 outlets situated throughout the UK.

Radiation Survival
A wealth of information about surviving radiation emergencies.

Sportsman's Guide Military Surplus
I've been very satisfied with almost all of my purchases. Those few unsatisfactory have been promptly refunded.

Toxic Substances & Disease Registry Publications List
ATSDR is directed by congressional mandate to perform specific functions concerning the effect on public health of hazardous substances in the environment.

SurvivalistBoards
Extensive no-nonsense message board system. Many features including product ordering.

US Joint Services Manuals
An extremely comprehensive collection of field manuals and other military manuals - free downloads.