The American Medical Association http://www.ama-assn.org/ A substantial site with extensive information on health and disease unlike many Medical Association sites which tend to concentrate on the demands of doctors.
The British Medical Association http://www.bma.org.uk/ A fairly glossy site without much information. Mostly concerned with representing and protecting doctors.
The General Medical Council http://www.gmc-uk.org/ A very limited site with a few brief guidelines for doctors in ethical matters and information on registration procedures.
