Free continuing medical education (CME) courses online and live are listed.
Because the courses have no charge and provide a small number of credits each, most are sponsored by either a pharmaceutical company or medical device company. While they do not specifically endorse a product in the course, they are usually structured to highlight a problem for which the sponsoring company has a solution. Most physician understand this dynamic implicitly.
If you are looking for a more comprehensive review there are a variety of internal medicine board review courses from CME-providing institutions like the Harvard, Hopkins, the Cleveland Clinic, and NYU.