I am still a newbe, but here is what have figured out so far:

Website - just ok, not updated very often and only in large buckets
800 number - better, with some more detail
BMWNA Rep - about the same as the 800 number
Dealer Rep - they seem to know the most

That said, my car was schedule for production week 41, which is this week. The rep called me today to tell me its on a truck and on its way here, no complaints from me!