This may have been around for a while, but just in case you have not seen it, here is the information that BMI provides on podcasting a nd their licensing agreements.
“Podcasting is the latest wave in online music. BMI offers a new media license that clears the public performing rights for thousands of businesses and individuals with easy, low cost licensing options. BMIâ€™s agreement only covers public performance rights to musical works in the BMI repertoire. You will need to secure additional licensing from music publishers and record labels for mechanical rights in the underlying musical works and for uses of master sound recordings in your podcast.”