Nielsen recently released some survey results for June 2011. According to their findings, Android is the most-used mobile OS. They have 39 percent of the market. Apple’s iOS is second largest at 28 percent. RIM’s BlackBerry is at 20 percent.
Still, Nielsen does note that Apple is the only company that makes phones running on iOS, meaning that Apple is the top smartphone maker in the US. HTC is second, their handsets make up 14 percent of the US smartphone market.
Windows Phone 7 is about six percent of the smartphone market and Motorola devices make up 11 percent. There’s more data at Nielsen’s official blog, and it’s worth checking out for a better breakdown.