The Android operating system has moved past Apple in the US mobile phone market in the first quarter of 2010, to take the number-two position among smartphone operating systems, according to a research from market research firm The NPD Group.

The NPD’s wireless market research has revealed that based on unit sales to consumers last quarter the Android operating system moved into second position at 28% behind RIM’s OS (36%) and ahead of Apple’s OS (21%).

According to NPD’s Mobile Phone Track, strong sales of the Droid, Droid Eris, and Blackberry Curve via these promotions helped keep Verizon Wireless smartphone sales on par with AT&T in the first quarter. Smartphone sales at AT&T comprised nearly a third of the entire smartphone market with 32%, followed by Verizon Wireless 30%, T-Mobile 17% and Sprint 15%.

The firm said that the popularity of messaging phones and smartphones resulted in slightly higher prices for all mobile phones, despite an overall drop in the number of mobile phones purchased in the first quarter.

The average selling price for all mobile phones reached $88 in the first quarter, an increase of 5% compared to same period last year. Smartphone unit prices, by comparison, averaged $151 in Q1 2010, a decrease of 3% over the previous year.

Ross Rubin, executive director of industry analysis for NPD, said: “As in the past, carrier distribution and promotion have played a crucial role in determining smartphone market share. In order to compete with the iPhone, Verizon Wireless has expanded its buy-one-get-one offer beyond RIM devices to now include all of their smartphones.

“Recent previews of BlackBerry 6, the recently announced acquisition of Palm by HP, and the pending release of Windows Phone 7 demonstrates the industry’s willingness to make investments to address consumer demand for smartphones and other mobile devices.”