If you’re an author, or if you are just curious, you might want to go over to Dear Author and take a look and Jane’s FAQ. Here’s an excerpt:
At the suggestion of Peter Brantley of the Internet Archive, I offer up this Frequently Asked Questions for Authors regarding the Text To Speech (TTS) functionality that is the subject of debate. This may be an evolving document as more people provide input so that it adeqately addresses the issues. Please feel free to offer suggestions and/or revisions in the comments section.
Q: I’ve heard that there is some debate over Kindle’s Text to Speech Function. What is it and should I be concerned?
A: When Amazon released it’s Kindle 2 in February, it announced that it had included the ability for every document/book/written work on the Kindle to be real aloud using a robotic voice (either girl or boy). You can hear a sample of it here as read by Wil Wheaton. The TTS functionality was switched “on” as a default. Author’s Guild objected to this on the basis that the right to read a book out loud was an audio right, a derivative right of authors under the Copyright Law.