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