http://nobelprize.org/medicine/
The web site of the Nobel Institute in Stockholm, Sweden. Within the site you can access the lectures given by all the Nobel Laureates in Medicine or Physiology. The early lectures are mainly text files but some, especially the more recent ones, are available in pdf format and contain useful illustrations. The same site also has the lectures given by Laureates in Physics and Chemistry.

http://student.bmj.com/
The studentBMJ is an international magazine for medical students and is available free on the web. It contains a wide variety of articles on clinical and non-clinical topics that have been specially commissioned with medical students in mind. Not always the best source but can be informative.

http://www.historyofnimr.org.uk/mill-hill-essays/
This link provides access to the series of essays written by members of the National Institute  for Medical Research.  Their main objective was to provide detailed information on scientific issues of interest for the general public. A wide variety of biomedical topics were covered and remain a helpful introduction to various fields of research.