Seeking Alpha summarizes findings by MacObserver forum members who have been compiling iPhone IMEI numbers into a public spreadsheet.
According to those numbers, it appears that Apple may have already reached 10 million iPhone sales for 2008. According to the sequential Type Allocation Codes (TAC), Apple has reached 9.2 million iPhone 3Gs manufactured. When combined with the sales figures 2.4 million 1st generation iPhones sold earlier this year, it brings them well above the 10 million mark even if over a million 3G iPhones remain in the sales channel.
SeekingAlpha notes there are a few assumptions that may introduce some error into these estimates:
The actual number of handsets sold versus manufactured depends on a variety of factors including the amount of inventory Apple carries in its retail chain, defects that were destroyed, defects that were sold and then exchanged, display models etc.
A goal of 10 million iPhone sales in 2008 has been Apple's stated goal when first announced the iPhone in January 2007.
http://seekingalpha.com/article/98619-iphone-sales-drastically-surpass-q4-consensus-apple-reaches-10m-goal?source=yahoo