you can get them on audio book at
www.audible.com
You can buy them outright and download them from the site at normal price or you can join for $14.95 a month. With that memembership they give you one credit a month and with your credits you can get most of their books. I have belonged for about 3 years now and I really like the convinence.
I love listening to audio books while I sew. It makes the passage of time that much more pleasant for me, especially since I mostly sew alone.