• National Library of Medicine Medline Plus
• EurekAlert
• WebMD
• Centers for Disease Control (THE authority on swine flu and travel meds)

• The Mayo Clinic (highly recommended)
• Excellent self-care advice and information about common conditions from the American Academy of Family Physicians
• National Library of Medicine Medline Plus (drugs, health topics...)
• National Institutes of Health (authoritative documents and info)
• Health Finder (various USA government publications)
• Merck Manual of Medical Information -- Home Edition
  (intended for the general public)
• Merck Manual (intended for health professionals)
• Merck Manual in Italian (Manuali Merck)
• UpToDate (especially useful regarding procedures and treatments)
• University of Maryland Medical Center (health topics)
• WebMD

Resources for patients with uncommon diseases:

• NIH Office of Rare Diseases
• National Organization for Rare Disorders

• Alcoholics Anonymous
  • AA Europe, Rome page
  • AA Rome site
• American Academy of Orthopedic Surgeons: information/brochures on topics from bunions to joint replacement (also en espanol)
• Diabetes and its treatment: American Diabetes Association, Joslin Clinic
• High cholesterol: concepts and treatment
  • WebMD
  • National Institutes of Health
• Dietary advice:
  • Healthy eating: Dietary Guidelines for Americans 2005
  • Diabetes: National Institutes of Health or American Diabetes Assoc.
  • Gastrointestinal + other conditions: Jackson Gastroenterology
  • Weight Watchers
  • A proposed diet for hypertension:  the DASH Eating Plan
  • Metabolic rate calculator: learn how many calories you burn
  Spousal abuse (very useful essay and links, from the Mayo Clinic)
• Survivors of sexual violence: Pandora's Acquarium
• Travel information:

  • Centers for Disease Control (authoritative and up-to-date)
    • "Yellow Book"
  • MD Travel Health (also useful)
• Irritable bowel syndrome:

  • IBS self-help and support group
• Digestive conditions and procedures: Jackson Gastroenterology
• Migraine: The Migraine Action Association (self-help group)
• Mental health:  yet another excellent offering from the Mayo Clinic
• Self-administered Cognitive Behavior Therapy: MoodGYM. Intended to help people who are having mild problems with anxiety and depression, not for people with clinical disorders.
• Dealing with grief, death, and major loss: GriefNet.org
• Menopause
  • Mayo Clinic Women's Health Center
• Postmenopausal hormone therapy
• Sexual issues - Our Bodies Our Selves
• Stress and its effects on health: The End of Stress As We Know It
• X-rays: good information on imaging studies
• Colonoscopy

For non-Italian physicians considering coming to work in Italy:

The Ministry of Health has a web page with information on how to get foreign medical training recognized here. Unfortunately as of now it is only in Italian.