I have audible account and it was easy to listen to audible books on my iPhone (audible app). I just got the Nokia lumia 900. What is the workaround to get books on to the lumia?
Supposedly Audible app for WP7 is in development. You might try contacting Audible to see if they will let you into the beta test. I haven't had any luck with that myself so just waiting for the app to be release in production.
I've never used the Audible App, so, assuming a few things...
The files are just standard MP3s
The album/track info is correct
Then all the chapters for the audio book will be listed under the same artist. You can right click on that artist/album and choose Add to playlist. Create a new playlist so you can quickly find your audio book.