Allnurses.com -- is a networking site for nurses and nursing students.
MedlinePlus -- a service provided by the U.S. National Library of Medicine, MedlinePlus provides information "... about diseases, conditions, and wellness issues in language you can understand. MedlinePlus offers reliable, up-to-date health information, anytime, anywhere, for free. You can use MedlinePlus to learn about the latest treatments, look up information on a drug or supplement, find out the meanings of words, or view medical videos or illustrations. You can also get links to the latest medical research on your topic or find out about clinical trials on a disease or condition." Useful for patient education.
Merck Manual, Professional Version -- first published in 1899 as a "service to the community," as of April 2015, the Merck manuals will no longer be published in print, but are now all digital. The Professional version retains its orientation to healthcare students and practitioners. There is a Consumer Version for patients and caregivers.
Spanish Health Information Portal -- free, authoritative health information from the National institutes of Health.
Evaluating Internet Sources-- Rely on this helpful site, made available by the undergraduate library at the University of Illinois at Urbana-Champaign.
Evaluating Resources -- from Berkeley Library, University of California. Note: these evaluation techniques are of use in assessing the authority of print resources as well.