Audiobooks HQ is an app from Inkstone Mobile, which offers more than 7850 classic and contemporary audiobooks for free. The app itself costs $1.99, but after that there is no further cost. It is accessible with VoiceOver and now offers VoiceOver support as well.
https://itunes.apple.com/us/app/audiobooks-hq-7850+-free-high/id573235547?mt=8