drkoop.com
Medical search engine managed by the Dr. Koop LifeCare Foundation.

healthatoz.com
Medical search engine and articles managed by Medical Network Inc.

healthfinder.com
Put out by the U.S. Dept. of Health and Human Services, this site offers a health search engine along with information on timely health topics.  Includes medical dictionaries, encyclopedias, journals, etc.

Internet Mental Health
Extensive information on a variety of mental health conditions.

Library Spot Medical
Excellent springboard into medical topics, information, conditions, etc.  Highly recommended.