In my experience it use to be the case you would get preordered items by the release day or before but not lately. I have been beyond frustrated the last few items I have pre-ordered. One book I ordered did not even get shipped for almost a week after the release date. I did do free super saver shipping. I am not doing any more pre-orders if I want to get the item quickly.
The Twilight disk took more than a month.

ps most of these items I ordered months ahead.