Here is their press release:
Kindle 2’s experimental text-to-speech feature is legal: no copy is made, no derivative work is created, and no performance is being given. Furthermore, we ourselves are a major participant in the professionally narrated audiobooks business through our subsidiaries Audible and Brilliance. We believe text-to-speech will introduce new customers to the convenience of listening to books and thereby grow the professionally narrated audiobooks business.I'm not going to rehash the stance I took two weeks ago. If you want to read my opinion, go here.
Nevertheless, we strongly believe many rightsholders will be more comfortable with the text-to-speech feature if they are in the driver’s seat.
Therefore, we are modifying our systems so that rightsholders can decide on a title by title basis whether they want text-to-speech enabled or disabled for any particular title. We have already begun to work on the technical changes required to give authors and publishers that choice. With this new level of control, publishers and authors will be able to decide for themselves whether it is in their commercial interests to leave text-to-speech enabled. We believe many will decide that it is.
Customers tell us that with Kindle, they read more, and buy more books. We are passionate about bringing the benefits of modern technology to long-form reading.