I don't really know any audio self-publishers but have you heard Money Room? Listen to one of their shows. If you like it you can sign up for their archive of shows for $20, or you can buy MoneyRoom shows/specials with top internet marketers on CD.
/ , http://www.moneyroom.com/archives.htm
I am not affiliated with Money Room in any way, I just tend to enjoy it.
Another idea is to look for normal audio books on CD at Amazon.com. Business, marketing, self-help, fiction are all made into them. For me, a good audio Bible is worth more than its weight in gold.
Hope this helped,