Salud!  A toast to your health!  Keep a healthy body and sane mind with these useful databases.

The Merck Manual On-Line 

http://www.merck.com/mmhe/index.html

The Merck Manual Medical Library is the hypochondriac's dream.  This is an in-depth guide to health and the human body, easily searchable by topic or key word.

Anatomical Maps 

http://www.innerbody.com

This site has interactive maps of the different systems of organs in the human body.

Bartleby 

http://www.bartleby.com

This site seems to come up a lot, doesn't it?  Bartleby has the full text of Grey's Anatomy (loosely based on the TV show, apparently).  Read up on your Zonule of Zinn!