Although Apple's share of the US smartphone market remains slightly ahead of Google's, more buyers in the last six months picked a device powered by the latter's Android OS, Nielsen said today.

According to a November survey by the polling company, an Android handset was selected by 41% of US adult smartphone buyers in the last six months. Apple's iPhone accounted for 27% of the purchases, while a BlackBerry device was the choice of 19%.

That means Android smartphones enjoyed a 3-to-2 advantage over the iPhone, and a 2-to-1 lead over Research in Motion's BlackBerry.

Android has surged as consumers' mobile OS choice since June, when only 28% of those polled by Nielsen said they'd bought a Google-powered smartphone in the previous half year.

Nielsen's number jibe with those from a survey of US consumers conducted last September by ChangeWave Research, which found that of those who planned to buy a smartphone in the next 90 days, Android was to be the pick for 37%, a gain of seven percentage points since a similar poll in June. Apple's iPhone, meanwhile, plunged from 50% to 38% as the preferred smartphone in the same interval.

ChangeWave has not yet released the purchase plans survey it did in December.

Despite the recent boost in Android buying, Apple maintained its No. 1 spot as the market share leader among US consumers, Nielsen said.

Apple's iPhone accounted for 28.6% of all owned smartphones in November, while Android devices collectively had a 25.8% share. BlackBerry OS held a 26.1% share.

The numbers for all three were within the survey's margin of error. "Apple's clear lead over Android notwithstanding, this race might still be too close to call," Nielsen said in a post to a company blog Monday.

Apple's lead over Android has shrunk dramatically since June, according to Nielsen's data. Last summer, the iPhone had a US consumer market share of 27.9%, while Android's was just 15%.

Since then, Apple's share increased by less than a percentage point, while Android's climbed more than 10 points.

Data of another kind was released Saturday, when Internet metrics company Net Applications noted that online users of Apple's iPhone outnumber Android's by more than 2-to-1.

Net Applications, which measures online usage share, said that the iPhone was used by 1% of all people worldwide who surfed the Web last month. Android's global online usage share was 0.4% and BlackBerry's was only 0.13%.

No single Android-based smartphone maker has managed to sell as many handsets as Apple. Samsung, the largest seller of Android phones worldwide, sold an estimated 6.6 million Android devices in the third quarter of 2010. During the same period Apple sold 14.1 million iPhones .