The Kindle DX Product Link
in Alex's front page news reveals that:
Kindle DX can read to you. With its Text-to-Speech feature, Kindle DX can read books, blogs, magazines, and newspapers out loud to you, unless the book's rights holder made the feature unavailable. You can switch back and forth between reading and listening, and your spot is automatically saved. Pages automatically turn while the content is being read, so you can listen hands-free. You can speed up or slow down the reading speeds or choose a male or female voice. In the middle of a great book or article but have to jump in the car? Simply turn on Text-to-Speech and listen on the go.
But, of course, you know this will mean, no support...