Lullaby (Watersong #2) by Amanda Hocking

Sequel to WAKE, the first book in the phenomenal new series by bestselling author Amanda Hocking.
Expected publication: November 27th 2012 by St. Martin's Griffin  
  
First book is:

Lose yourself in the magic of Watersong, an unforgettable new series about two sisters who nearly lose their lives - and their loves - when they fall under the spell of three beautiful but deadly sirens.