Have you considered podcasting your lessons? This might be of interest to you.
Let me know if you decide to podcast.
Sharing audio and video files on the Web has been possible for most of the last decade. But in the past two years podcasting has exploded onto the scene.
This paper examines educational podcasting in three realms: the creation and distribution of lecture archives for review, the delivery of supplemental educational materials and content, and assignments requiring students to produce and submit their own podcasts.
From the Office of Technology for Education and Eberly Center for Teaching Excellence at Carnegie Mellon University, this is a 15 page PDF.
Podcasting: A Teaching with Technology Whitepaper