A new book, based on Tolkien's notes and written by his son Christopher, called the Children of Hurin is due to be released. The book will be illustrated by Alan Lee, who worked on the films. Parts of the story appeared in the History Of Middle Earth (and Hurin is mentioned in The Silmarillion).
Fairly exciting news if you're a Lord of the Rings fan. I always thought some of the stuff in the The Silmarillion had some interesting scope and stories I would like to see in more depth such as the tales of Tuor and Turin.