The Federal government has launched an intensive web-driven campaign through a new platform at PandemicFlu.gov to disseminate information on potential pandemic-level flu outbreaks. Each state has its own sub-site linked into the broader federal platform, with an impressive coordination of relevant information across a large network of local interests.
CDC Index of Public Health Social Media Tools
CDC YouTube Channel
CDC Swine Flu Portal
WHO Influenza A(H1N1)
CDC-TV (see below)
State Department Pandemic Influenza Fact Sheet