The website audible.com provides audiobooks as downloads in .aa format for subscribers. I've been a subscriber for over a year, and it's a pretty good deal. Some time ago they offered a collection of science fiction and fantasy stories featuring CAS's Master of the Crabs (which I note is posted on this site in MP3 format) and a Jirel story by C. L. Moore. As of yesterday audible.com has posted a collection of Zothique stories, which I have downloaded but not yet listened to. The collection was done by Zikkurat Productions.

I've finished listening to the audiobook. It has "The Weaver in The Vault", "The Charnel God", "The Isle of the Torturers" and "The Black Abbot of Puthuum". I had mixed feelings about it. The narrator spoke in an exaggerated voice meant to sound sinister, and there were long gaps in the narration filled with relatively undistinguished mood music. If you listen to "Isle of the Crabs," available on this site in MP3, you get the idea. But on the whole I enjoyed listening, and thought it was a nice effort.

Too bad they don't have the collection anymore, now they sell each individual story for 4.95 each (member price.) I personally LOVE the readings. Very atmospheric. You can listen to 10 minute samples on the site for free. Check 'em out...