A quick update: Yesterday, I mentioned that you can grab on Google Books and Scribd a free e-book of Chris Anderson's latest work, Free: The Future of a Radical Price. Today, I discovered that you can also download an audiobook version of Free over at Audible.com. It will cost you nothing. But you will need to register with Audible, providing name, email, username, etc. If you find that you live in a geographical market that Audible won't serve, then you can download a universally free version at Wired.com's web site. The page is here, and the zip file is here.
Separately, if you start a 14 day free trial with Audible, you can download two free audio books. This will give you access to many current bestsellers (Malcolm Gladwell, David Sedaris, Barack Obama, etc.). Whether you stick with the membership (as I did), or cancel, you can keep the free books. Get more details here.
Lastly, if you want many other free audiobooks, check out our big collection of classics.