The long awaited Audible app is coming to Windows Phone. Currently is in private beta stage, and is expected to arrive in Marketplace in next few weeks.
Check the video overview of the upcoming Audible app for Windows Phone after the break

-Primary Live Tile that flips with recent history on the back
-Secondary Live Tiles based on book title; enables 1-touch playing of audio; flips to show bookmark history
-Configurable "jump back" feature to re-hear a section (default is 30 seconds)
-Button - less playback which uses gestures instead of buttons to control the audio
-Badges and statistics viewer
-Sharing of book info and general news via the Windows Phone built in social networks