Augmenting lectures: The lecture is retained as-is, but additional material is provided such as pre-lecture "teasers", post-lecture summaries and discussion of difficult concepts (based on feedback), and more general discussion of related issues to inspire interest in the topic (e.g. MP3).
Changing lectures: Instead of watching a podcast alone, why not watch it in small groups and hit the pause button to discuss, make predictions, etc. We can support this by explicitly building these activities into the podcast ("Now, let’s pause to discuss the following question ..."). Although discussion could take place online, face-to-face discussion is more natural and easy (we are better at talking than typing). This discussion may involve a staff mediator ("guide"), in which case the face-to-face lecture could be dropped entirely (e.g. PDF).
Learner-created content: Students can produce a range of resources such as educational material covering a given topic (since a good way to learn something is to teach it), pre-lecture "teasers", post-lecture summaries etc. Generally applicable pedagogical considerations include how to set explicit and clear learning goals, and how to effectively convey structure.
The presentation will discuss these uses of audio/video, considering a range of podcast formats. It will also survey research that has been done on usage patterns (e.g. finding that podcasts are often viewed on PCs) and on pedagogical ("podagogical"?) issues.