The American College of Allergy, Asthma & Immunology (ACAAI) has started publishing free podcasts/videocasts from the 2006 Annual Meeting:
"Every second week, the College will post a new 30-minute Vodcast (video podcasts) of a key presentation from its 2006 Annual Meeting on-line. Each vodcast will contain the original audio and presentation slides and can be viewed from a computer or downloaded to a portable media player (like an iPod)."
Cleveland Clinic has had free podcasts for both patients and health professionals for a while.
Free Audio and Video Podcasts for Health Professionals by Cleveland Clinic
Cleveland Clinic Offers New Podcasts
Video Podcasts by The Cleveland Clinic