Originally Posted by ghostyjack
As audiobooks are normally spoken versions of the books (there can also be adaptations that can fall in this catagory that do not follow the books word-for-word), they can be categorised is a similar way to ebooks (e.g. author, series, book X of Y, etc) but will also need metadata about the audio file. In a nut-shell, it's a combination of books and audio file information.
Also if the audiobook manager is capable of playing them back, then they would need the ability to bookmark the played audiobook file, so you can return to that point and continue listening.
iTunes would seem the obvious answer.