Apple’s US carrier partner, AT&T, sure has one big smile on its face — it has recorded the highest number of iPhone activations ever and is stealing swathes of cellphone market share from its competitors. The company’s financial results announced today confirm it activated 3.2 million iPhones in its just gone quarter. (It also made $30.8 billion in revenue in the period).  That comes with much help from the iPhone, which the carrier again stated it was activating new units at a clip of 10 times the iPhone 3GS the previous year. “On June 24, AT&T began offering iPhone 4, the most powerful iPhone yet. Preorder sales of iPhone 4 were 10 times higher than the first day of preordering for iPhone 3GS a year earlier. For the full second quarter, AT&T iPhone activations totaled 3.2 million, the most quarterly iPhone activations ever. Approximately 27 percent of those activations were for customers who were new to AT&T,” the company said. The company also delivered substantial year-over-year wireless margin expansion, it said. The number of 3G postpaid integrated devices on AT&T’s wireless network increased by 2.9 million to 29.7 million, an increase of 98.2 percent year over year and 10.8 percent sequentially. More here.