Mine dispatched on the 18th, was "In Transit" for 2 days and now is just "Dispatched" again.
Yet to receive a usable tracking number.
The Apple Store order history thing is down right now. When it comes back up, sign in, look in order history, hit track delivery, you are looking for a long one starting with 1Z
If it's not there, are you sure it's coming via UPS? Might be worth a chat to someone at apple to see if they can give you the tracking reference.