Pandora.com, the internet radio site (the best one, in my opinion), has a lesser known podcast. Its not quite what you would expect though. They do a 10 minute study every two weeks on different methods of music. For example, they have meters & time Signatures, recording vocals, mixing vocals, studies on harmony, pedal point, major and minor, chords, as well as drumming. Its very much worth the listen if your at all interested in the mechanics of music or recording. Here is their main page, or you can subscribe via iTunes.