It’s no secret that Samsung’s flagship Galaxy smartphones are leading the Android-powered pack of handsets. What may be less obvious is just how quickly the company is closing in on Apple’s title of world’s biggest smartphone vendor in unit terms. Samsung announced on Friday it expects its third-quarter profit to top even the most bullish market forecasts, driven in large part by booming smartphone sales. “The Galaxy S II probably played a key role in boosting the company’s earnings and it will continue to do so pretty much unchallenged, until Apple unveils a better new version of iPhone,” said Kyung Woo-hyun, a fund manager at Daishin Asset Management.

Sprint had a rough start to the week and an even rougher end to it. The No.3 U.S. wireless carrier signaled on Friday that it could spend more money than it brings in over the next few years, even without accounting for the high costs of selling the Apple iPhone, sending its shares down 13 percent. On Monday, the Wall Street Journal reported that Sprint would likely lose money on its deal to sell the iPhone until 2014.  Sprint outlined a plan on Friday to spend $7 billion on a network upgrade, which it said it would pay for with cash from its balance sheet and by raising capital. The company refused to address the cost of selling the iPhone.