Although there are several thousands of health sites, the quality of information is very varied. There are now several 'gateway sites' which provide access to good quality health information sources, sometimes with gradings or star ratings.
Health on the Net
http://www.hon.ch/ International foundation with code of conduct for quality health sites
Britiannica Internet Guide
http://www.ebig.com/ Includes section dedicated to health with star ratings
http://omni.ac.uk/ Organising Medical Networked Information - gateway to quality UK internet resources in medicine and health care
http://www.healthfinder.gov/ US government gateway providing links to hundreds of consumer health information web sites, including government and voluntary agencies, databases, on-line publications and support groups
No endorsement of the sites is intended by the NHS or the Centre for Health Information Quality and neither the NHS or the CHIQ carry any responsibility for their content.