According to DigiTimes, Apple has been ordering VGA lens kits (for use with the new front-facing camera on the iPhone 4) from supplier Asia Optical (AO) since May, to the tune 3 million (on average) per month. This is great news for AO, of course. If the current rate continues, they expect to get out of the red and reach profitability by the second quarter of this year.
It's also good news for customers, as it suggests that Apple is stockpiling a whole lot of units. Pre-orders begin in the US and elsewhere on June 15, and sales of iPhone 4 will begin in the US on June 24th. At the current rates, Apple could likely produce 9 million iPhone 4s by its fourth fiscal quarter of the year ending September.
Earlier this year, higher-than-expected demand caused shortages and delays for iPad customers. In fact, the international launch was pushed back about a month due to supply and demand trouble. That's definitely something Apple wants to avoid with iPhone 4.