Lots of people have been asking, so here you go. You can preorder a signed hardcover copy of ONE OF US WILL BE DEAD BY MORNING now from this link.
The book is released in hardcover by Thomas Dunne Books on 5 December, and pre-orders will be shipped by that date (if not a little before). You can also order the book from Amazon, Barnes & Noble, The Book Depository, Indiebound and all other good bookstores. Ebooks are also available, and an audio version is coming soon.