Flu:
The white house website on pandemic flu
The King County website on pandemic flu
Mirror of Daniel Ferrer's website on face masks as a partial solution to pandemics
Bird Flu Masks, a British commercial site
This website has a picture of avian flu virons
The Public Broadcasting Service's website on "Influenza 1918"
NBC Dateline website
Preparedness:
The U.S. Department of Homeland Security's preparedness website
3 days/3 Ways vendor list
Other:
Bleach and water
The Merriam-Webster Online Dictionary