AT&T said that it activated 2.4 million new iPhone 3Gs during the third quarter of this, resulting in payments of about $900 million to Apple, which means that the carrier subsidizes every iPhone 3G sold with about $375.

However, the investment is paying off as the company announced it expects its dilution associated with the iPhone 3G will run above its previous expectation, driven by iPhone 3G users that drive higher revenues and margins than other cellphone customers. According to AT&T, the average revenue per iPhone 3G user is about 60% higher than the average revenue of regular cellphone users. AT&T declined to provide exact numbers, but since we know that the average revenue per user (ARPU) is typically in the $51-$53 range, the average iPhone user should bring in somewhere between $80 and $85.

AT&T said that about 40% of iPhone 3G buyers are new to AT&T and iPhone users in general are more likely to stay with the carrier for a longer period of time. The iPhone 3G also drove subscriber additions for AT&T during the quarter: Retail postpaid net subscriber additions of 1.7 million were up nearly 40 percent versus results in the year-earlier third quarter and accounted for more than 85 percent of AT&T's 2.0 million total wireless net adds.   

It is also worth noting that AT&T is now seeing a huge increase in wireless data revenue, most likely due to the iPhone 3G. The carrier said that wireless data revenues grew 50.5% versus the year-earlier quarter to $2.7 billion. Wireless Internet access revenues more than doubled versus the results for the year-earlier quarter, and multimedia message volumes were also more than double third-quarter 2007 levels, AT&T said.

Overall, AT&T reported sales of $31.3 billion for the quarter. The net profit was $3.2 billion.