Considering the phone launched worldwide, I am pretty impressed that my local Apple store in north Miami/dade county(Aventura mall) has a line ALL DAY since launch and hasn't turned away one person that wanted an iPhone.
This time for launch seems Apple had a lot more pre-launch production going on.
So very soon they'll equal stock versus demand throughout the country.
It took them 3 days to sell 1 million of the 3G phones. It took them 74 days to sell 1 million of the V1 phones. Obviously this is also a function of how many more countries it went to but they also learnt from the V1 release.