I love Radio Plays and Audio Books, and wanted to mention these for anyone who does not already know of them. Escape Pod is a podcast that delivers a weekly free Sci-Fi audio story, and has been doing so since 2005. It is so successful at it that it is listed as a qualifying professional sale at the SFWA. In addition it has generated two spinoffs, Pseudopod for Horror fiction, and PodCastle for Fantasy fiction. You can subscribe to their podcasts, download the MP3 files from their sites, or got to the Escape Pod Archives searchable collection at Wikipedia.