Chapter 2 of Towers of Midnight entitled, "Questions of Leadership", has been made available online for free by Macmillan Audio in association with Tor.com. The chapter is narrated by Kate Reading and Michael Kramer.
This chapter brings the total number of available chapters for the book to four. The prologue was released as an eBook several weeks ago and can be purchased online. Chapter 1, "Apples First", can be found on Tor.com or Orbit's UK website. Chapter 7 (the first Mat point-of-view chapter) was made available recently on Brandon Sanderson's website, and can also be read right here on Dragonmont.
You can listen to Chapter 2 for free
here