On Monday, Apple published a press release that it had sold one million iPhone 3Gs as of Sunday. Piper Jaffray analyst Gene Munster agreed, but pointed out that Apple’s definition of sold is not what it seems.

The catch is that Apple counts iPhones sold in its stores as an immediate sale, but iPhones delivered to AT&T and overseas carriers also count as a "sale" into the channel. That iPhone may still be in transit, in the warehouse, or on the shelves but may not yet be actually sold to the end customer.

Mr. Munster’s estimate of the actual number of iPhones sold over the weekend was initially 425,000 worldwide. Later, that was revised to the 1M number sold worldwide.

Of course, considering the demand for the iPhone 3G, those "sold" iPhones in the process of being delivered to carrier partners are likely to go very fast and won’t sit on the shelves for long. In fact, the new iPhone 3G is sold out in many locations. As a result, the channel sales may be roughly the same as the customer sales. In comparison to the initial launch in 2007, Mr. Munster pointed out that it took 74 days for Apple to sell one million iPhone 2Gs.

Mr. Munster, in a note to investors obtained by iPO, forecasted that Apple would sell 4.1 million iPhone 3Gs by the end of September. The demand for the new Apple smartphone must be tempered by constrained supplies, he said.

The PJC analyst provided an estimate, by country, of the iPhones sold into the channel over the weekend:

Source: Piper Jaffray