They had around 3 million for the launch
I have information that leads me to believe that less than 500,000 were made. This is a number from one of Apple's suppliers.
With all of the potential v1.0 problems, and I'm sure a little bit of intentional artificial scarcity, 500,000 makes sense to me.
It has been estimated that 200,000+ have been sold so far and I'm sure Apple is set up to ramp production quickly if demand warrants. I don't think they would want to potentially rework an extra 2,500,000 v1.0 iPhones in the event of a serious hardware or software bug.
These days the name of the game is just in time manufacturing, 3,000,000 doesn't make sense if they think they are going to sell 10,000,000 in 18 months. Apple and ATT probably want less than 100,000 in inventory at one time.