I got an email yesterday (10th) from the book's USA distributor, with the following message:
"The stock for Mastering the Nikon D7000 was received this morning by our warehouser and will begin shipping to customers within the next couple of days."
Preorders will be filled shortly and the book will be generally available on Amazon.com, BarnesAndNoble.com, OReilly.com, and in fine bookstores. There is so much information in this book that it ought to be worth the wait.
We are putting some methods in place that will allow future Mastering books to be available more quickly. I truly appreciate the patience of the thousands of Nikonians who have preordered the book.