• by Mark Walsh  @markfwal, August 4, 2010

Following earlier reports this week of an Android explosion, market research firm NPD Group said Wednesday the Google mobile operating system had surged past BlackBerry to become the top-selling smartphone platform in the second quarter.

Android accounted for one of every three smartphones purchased in the second quarter, well ahead of Research in Motion's BlackBerry OS, with 28% market share, and Apple's iOS, at 22%. BlackBerry dropped from 37% a year ago and was knocked out of the of the top slot for the first time since the fourth quarter of 2007.

NPD caused a stir in May when it reported Android phones for the first time had outsold the iPhone in the first quarter.

But the firm's report is already the third this week to confirm the rapid rise of Android as a major force in the smartphone wars. Research firm Canalys on Monday said sales of Android-powered phones shot up nearly 900% in the second quarter compared to a year earlier, giving it a 34% share of the U.S. market. RIM had 32% and Apple, 21.7%. RIM had 45% in the year-earlier period.

A separate report from Nielsen showed that Android had pushed past the Apple iOS over the last six months to grab a 27% market share, while BlackBerry slipped from 39% to 33%. Overall, BlackBerry is still the biggest player, with a 35% share compared to 28% for Apple's iOS and 13% for Android, according to Nielsen.

RIM is counting on the BlackBerry Torch 9800 released Tuesday to reverse its sliding market share and get back into the smartphone race. The new device features a touchscreen and slide-out keyboard as well as the latest version of RIM's operating system, BlackBerry 6.

The phone launches as RIM is engaged in a standoff with the government of the United Arab Emirates over its planned ban of BlackBerry email and text-messaging services because of security concerns. Saudi Arabia followed suit Tuesday, ordering cell service providers to block BlackBerry service unless RIM meets security requirements.

For Apple, NPD pointed out that the second quarter brought a slight improvement (increasing share from 21% to 22%) with the debut of the iPhone 4 in late June and slowing gains by Android.

"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."

Since the iPhone 4 was only released at the end of the second quarter, the full impact on Apple's sales will not be reflected until the end of the third quarter. The company has said 3 million of the devices were sold in roughly the first three weeks of release.

As has often been noted, Android has an advantage over Apple's iOS in particular because the operating system has been adopted by multiple manufacturers and wireless carriers. The top-selling Android phones in the second quarter were the Motorola Droid, the HTC Droid Incredible and the HTC Evo 4G, sold by Sprint.

But if Apple ends its exclusive partnership with AT&T to sell the iPhone through Verizon by next year, as rumored, that could help it regain share from Android.