It will be a download that is available. More than likely, seeing as how most stores only allow pre-orders to pick up at Midnight; Walmart being the exception; the pre-order copies will likely have a code inside for Nuketown. So, it will likely go to all those who pre-order the game, period. Don't take my word on that, but that is what it seems to be. I don't think this offer will expire and I am beginning to doubt that this is the 2nd Wave reward. This pre-order incentive was leaked and Treyarch and Activision quickly owned up to it and put it all over the website and forums, yet, the second wave is still classified until 1pm EST. So, logic leans me towards saying that this is just something they added to get more pre-orders. This may also be just a little wishful thinking because Nuketown 2025 as a 2nd Wave reward would tick me off a little bit.