The Motorola Droid, sold as the Milestone in Canada, was the top-selling Android phone in the U.S. in the second quarter of 2010. (Russel A. Daniels/Associated Press)

Smartphones based on Google's Android operating system topped rivals in the United States for the first time, according to consumer tracking firm NPD Group.

Android phones — which are manufactured by a host of companies including Motorola and HTC and use Google's software — accounted for one-third of all smartphones sold in the United States in the second quarter of 2010, the NPD report said. The gain came at the expense of Waterloo, Ont.-based Research in Motion and its BlackBerry phones, which slipped to second place with 28 per cent market share.

Apple's iPhone was third with 22 per cent of the market.

Android's supplanting of BlackBerry is the first time since the fourth quarter of 2007 that RIM lost its leadership position. At that time, it was Apple's newly introduced iPhone that took top honours.

"For the second consecutive quarter, Android handsets have shown strong but slowing sell-through market share gains among U.S. consumers," said Ross Rubin, executive director of industry analysis for NPD, in a statement. "While the Google-developed OS took market share from RIM, Apple's iOS saw a small gain this quarter on the strength of the iPhone 4 launch."

The top five selling Android phones, in order, were the Motorola Droid, the HTC Droid Incredible, the HTC EVO 4G, the HTC Hero and the HTC Droid Eris, NPD said. In Canada, the Android is sold as the Milestone.

The overall average price of a phone rose three per cent to $90 US over a year ago given the higher cost associated with smartphones. Smartphones themselves, however, saw an average nine-per-cent decrease in price to $143, the tracking firm said.

NPD's findings agree with those released this week by technology analysis firm Canalys, which found that Android phones accounted for about 34 per cent of the U.S. market in the second quarter. The company found that worldwide, the top three smartphone makers were Nokia, RIM and Apple.

The NPD report comes a day after RIM unveiled its latest device, the BlackBerry Torch, which is designed to appeal to the wider consumer market.