Free

• 1). Import the AA file into iTunes by dragging the file into the "Library" pane on the left-hand side. Authorize your Audible account within iTunes by selecting "Authorize Audible Account..." via the "Advanced" menu bar.
  
  
• 2). Create a new playlist by selecting "File" > "New Playlist" and add the audiobook to the new playlist.
  
  
• 3). Insert a blank CD into the computer's optical drive. Highlight the new playlist within iTunes and select "Burn Disc." Select "Audio CD" as the format and select the proper CD-ROM drive. Click "Burn" to begin the process. Once complete, iTunes will eject the CD. Re-insert the disc.
  
  
• 4). Highlight the disc within iTunes sidebar under the "Devices" header. Select "Import" to begin copying the files to your computer in the MP3 format. Once complete, the audiobook files will be in iTunes as MP3s. You can directly access the MP3 files via your computer's "Music"/"My Music" folder.
  
  

Paid

• 1). Download and install an audio conversion program. There are dozens of shareware conversion programs available on download repositories such as Download.com. Be sure to read the list of supported formats, as it needs to include the AA format. Not every conversion program includes this audio format.
  
  
• 2). Launch the program. Open the AA audiobook file by selecting "File" > "Open" if not automatically prompted. Depending on the application, you may be able to drag and drop the file onto the application's main window.
  
  
• 3). Configure the output settings to MP3 and designate a destination for the resulting file. This is handled differently by each application. Be sure to refer to the application's help files to understand the various output settings available to you.
  
  
• 4). Select "Start/OK/Convert" to begin the conversion process. Once complete, you will find the MP3 in the folder selected in the previous step.