DRM goes away if you burn an audio cd, not an mp3 cd, but audio...
And circumventing the DRM is a breach of copyright, under the terms of the DMCA. Audible say you have the right to copy your books to CD once, but their EULA doesn't carry the weight of law, and they're not the copyright holder, anyway. Technically, burning an Audible audiobook to CD is illegal.
I'm hoping that now that the music industry is figuring out that DRM is a worthless money sink, Audible will follow suit soon enough. I
want to be a customer of theirs, but while they continue to insist that I break the law in order to be able to listen to their content in the time and place of my choosing, I obviously can't do business with them.