Project Inform (www.projectinform.org/) - national non-profit community-based organization working to end the AIDS epidemic.
Kaiser Family Foundation (www.kff.org) - excellent information and materials.
National Minority AIDS Counci (www.nmac.org) - specific information about impact of HIV on African-Americans.
United Nations and World Health Organization (www.unaids.org/)
The Body (www.thebody.com/safesex.html)
Advocates for Youth (www.advocatesforyouth.org/)
Other Health-Related topics:
Facts on Tap (www.factsontap.org) campus-based alcohol prevention efforts.
Go Ask Alice! (www.goaskalice.columbia.edu/) Q&A website. Updated weekly. All questions are read and email addresses of inquirers are scrambled before reaching the webpage to ensure anonymity.
Dr. Grohol's forum (http://forums.grohol.com) - forum for mental health issues.
Centers for Disease Control (www.cdc.gov)