First, relax, this is genuine. Take a lok at
http://www.javaranch.com/pastwinners.jsp to see some of the people who have won books in previous promotions. Your name is listed near the bottom of the page. Congratulations!
Books are certainly sent out of the USA. The main problem is that the books are dispatched direct from the publisher, and some publishers are better/faster than others. I'm in England; I won a book a year or two ago and got it eventually. I have recently also won another, but not seen it "in the flesh" yet.
If you still have not received the book in a month or so, please contact
bookpromotion@javaranch.com and someone will do their best to find out what has happened to it.