In about two months since the launch, Verizon (s VZ) has sold 2.2 million iPhones, giving Apple (s AAPL) a big boost in the U.S., according to the New York-based phone company. Yesterday, AT&T (s T), till recently the sole seller of the iPhone, announced that it had activated 3.6 million iPhones. The two companies in total now account for a big chunk of Apple’s sales. Apple said that it sold 18.65 million iPhones during the quarter ending March 31, 2011.

With AT&T’s network woes continuing, don’t be surprised to see more folks switching to Verizon, as their contracts come-up for renewal. Verizon is widely viewed as a company with the best wireless network in the US.

In addition to the iPhone, Verizon said that it activated more than 500,000 4G devices including 260,000 HTC Thunderbolts which were available for only two weeks during the quarter. Verizon, which now has 104 million customers, says that nearly 60 percent of its total phone sales were smartphones. Verizon saw its wireless data revenues jump to $5.5 billion.

Like AT&T, the total wireless service revenue for Verizon grew marginally from the previous quarter – $14.3 billion during the January to March time frame as opposed to $14.2 billion during the fourth quarter of 2010. However, from the year ago time frame Verizon had total service revenue of $13.5 billion– which means year over year the operator saw a 6 percent rise in revenue.