I've just set up a store selling direct MP3 downloads of the Random House audiobook for my last novel, Makers, thanks to the good offices of Random House Audio, the eShop WordPress plugin, and Mike Little, my WordPress tech guy.
The Makers audiobook runs 18.5 hours and is formatted for burning onto 15 CDs. It's read by Bernadette Dunne. I really like Dunne's reading (here's a sample) and RHA's production job is tops. The MP3s are 128K/44KHz.
I get an additional 20 percent on top of my customary royalty if you buy it from me, and you get a book that has no DRM and no crappy "license agreement" requiring you to turn over your firstborn in exchange for the privilege of handing me your hard-earned money.
Right now, sales are only available through PayPal, though I hope that'll change soon. And if this is successful, I hope to add the audio for Little Brother and my forthcoming YA novel, For the Win.