Nielsen: iPhone in pole position, Android sales flat

Although Google is now activating 500,000 new Android devices each day, research firm Nielsen reports that Android smartphone sales to U.S. subscribers have flattened over the last three months. Android phones made up 27 percent of U.S. smartphone purchases between Mar. 1 and May 31, Android also accounted for 27 percent of new smartphones during the Dec. 1, 2010 to Feb. 28, 2011 period.

Apple's iPhone is now driving U.S. smartphone sales, representing 17 percent of smartphone purchases during the most recent three-month period, up from 10 percent during the previous three-month segment. RIM's BlackBerry continues to nosedive, sliding to 6 percent of smartphone sales from 11 percent during the previous three-month block. Microsoft's (NASDAQ:MSFT) Windows Phone 7 has remained consistent over the last six months, generating just 1 percent of U.S. smartphone sales.

Fifty-five percent of U.S. consumers who purchased a new mobile handset during the last three months opted for a smartphone over a feature phone, the first time smartphone sales set the pace in the American market, Nielsen reports. Just a year ago, smartphones made up 34 percent of U.S. handset purchases.

Smartphones now make up 38 percent of the addressable U.S. mobile market. Android remains the dominant platform, representing 38 percent of the overall U.S. smartphone market. iOS is next with 27 percent market share, followed byBlackBerry at 21 percent. Windows Phone 7 makes up 19 percent, and Microsoft's legacy Windows Mobile accounts for 9 percent.