1.5 million-ish iPhones have been sold, up to the point a few weeks ago that they started being sold internationally. There are 8.2 million people in NYC, which is 2.7% of the 301 million living in the USA. Assuming iPhones were distributed evenly across the US, that'd be something around 40,000 phones here.

But I'm guessing that they're not distributed evenly, and that the coasts and tech centers have many times more than the middle of America. If anyone has any other good leads, step on up!