Kindle 2 is not paying anyone for audio rights.

Op-Ed Contributor - The Kindle Swindle? - NYTimes.com
http://www.nytimes.com/2009/02/25/opinion/25blount.html

The Kindle 2 is a portable, wireless, paperback-size device onto which people can download a virtual library of digitalized titles. Amazon sells these downloads, and where the books are under copyright, it pays royalties to the authors and publishers.

Serves readers, pays writers: so far, so good. But there’s another thing about Kindle 2 — its heavily marketed text-to-speech function. Kindle 2 can read books aloud. And Kindle 2 is not paying anyone for audio rights.

True, you can already get software that will read aloud whatever is on your computer. But Kindle 2 is being sold specifically as a new, improved, multimedia version of books — every title is an e-book and an audio book rolled into one. And whereas e-books have yet to win mainstream enthusiasm, audio books are a billion-dollar market, and growing. Audio rights are not generally packaged with e-book rights. They are more valuable than e-book rights. Income from audio books helps not inconsiderably to keep authors, and publishers, afloat.