According to market researchers at NPD, Google's market share of the US smartphone market exceeded that of Apple's iPhone for the first time ever in the first quarter of 2010. Google's partners sold 28 percent of all smartphones in the US in the quarter, strong enough for a second place finish ahead of Apple, which had 21 percent of the market. RIM finished in first place, with its Blackberry devices controlling 36 percent of the US smartphone market.

NPD credits Google's multi-carrier approach for the win. Unlike the iPhone, which is only sold by AT&T, Google's partners sell Android-based devices from all major wireless carriers in the US. And some partners, notably Verizon Wireless, are offering special incentives to move multiple devices at once.

"As in the past, carrier distribution and promotion have played a crucial role in determining smartphone market share," says Ross Rubin, NPD executive director of industry analysis. "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."

Though Apple sold more iPhones in the quarter than it did in the same period a year earlier, the competition grew much more quickly, and iPhone market share was flat year-over-year. Android was the biggest gainer, and by a wide margin, and today there are 34 different Android devices available from a variety of vendors.

Of course, thanks to a two-year head start, Apple can still claim to have more overall users than Google's Android. Market researchers at comScore recently noted that 25 percent of all smartphone users in the US are on the iPhone, compared to 4 percent on Android (and over 40 percent on RIM Blackberry). But that gap will likely close over time, given Android's strong unit sales growth.

Android is also catching up with the number of apps available on the iPhone. While Apple claims a market of over 200,000 apps, compared to roughly 60,000 for Android, many iPhone apps are basically shovelware. So Google doesn't need to match the total number of iPhone apps as much as it needs to match the total number of useful iPhone apps. And that gap is clearly closing.

Of course, Apple has plans in place to thwart Google, including upcoming revisions to its iPhone OS and iPhone devices and the iPhone-based iPad. If all else fails, it can launch more patent infringement lawsuits against Android handset makers. It's first such suit, against HTC, was filed last month.