TW,

A few ideas...

Many sell their audio info products through ClickBank and Paypal, no different than marketing ebooks, reports, mp3's, podcasts etc...

There's also a few sites like...
http://www.learnoutloud.com/Catalog/Business
http://teach.learnoutloud.com/

If you want to do it with CD/DVD's...

David Vallieres highly recommends using... http://www.kunaki.com/
With his script... http://www.dvdautomator.com/

Phil