General Immunization Information

Centers for Disease Control and Prevention (CDC) 
CDC - Spanish Language Version 
National Immunization Program 
National Immunization Program Links to Related Sites
Morbidity & Mortality Weekly Reports (MMWR) Online 
National Center for Infectious Diseases 
National Foundation for Infectious Diseases 
How Vaccines Work 
Influenza or "the flu" vaccine 
The Children's Hospital of Philadelphia
The Arizona Partnership for Immunization Parent Page
Smallpox Information

Vaccine Safety 

Immunization Safety and Adverse Reactions 
Unprotected People: Real People and Real Diseases 
6 Common Misconceptions About Vaccination
National Network for Immunization Information
CDC-Vaccine Safety

Information for Health Care Professionals

Vaccine Information Statements (VIS) Online
VIS in Languages Other Than English
Public Health Training Network 
Vaccine Adverse Event Reporting System (VAERS)
Immunization Action Coalition - Free Health Education Materials

Immunization Coalitions

The Arizona Partnership for Immunization (TAPI)
Maricopa County Childhood Immunization Partnership (MCCHIP)
Immunization Action Coalition

County Health Departments