World Health Organization
World Health Organization: Avian Influenza (Bird Flu)
The World Health Organization (WHO) provides information, statistics, recent reports, and advice to international travelers regarding avian influenza--and features a "fact sheet" for concise and basic information on the virus.
Centers for Disease Control and Prevention
Centers for Disease Control: Avian Influenza (Bird Flu)
The primary access point for CDC-produced information about avian flu: key facts, current outbreaks, questions and answers, virus spread, eradication efforts and plans, travel advisories, and similar resources.