ECKERD Health Source - one stop source for formation on a variety of health issues.

Centers for Disease Control and Prevention - valuable resource to help with rare or obscure issues, the Travelers' Health section is a great tool.

U.S. National Library of Medicine - includes PubMed, a service that provides access to over 11 million citations from MEDLINE and additional life science journals. PubMed includes links to many sites providing full text articles and other related resources.