All of you freaking out because you have no change in your status need to chill. As many here have mentioned, this is exactly how every single other Apple pre-order situation has gone. Your status may or may not have updated to exactly what other people's status has, simply because it depends on the model you ordered, geographic location, when you ordered, etc.
If you ordered and your receipt says "Delivers on March 16," then you'll get it then. Stop obsessing.
Mine's been at 'Preparing for Shipment' since Sunday morning, and I have no doubt it'll be here on Friday as promised.