Each January, someone proclaims that finally, this year will be the Year of the Linux Desktop. Whether or not that ever comes true is a matter for another time, but what is certain is that 2010 is shaping up to be the Year of the Linux Phone.

It's no secret that Linux trails Windows and OSX on the desktop — Microsoft's stranglehold on the market in general and Apple's stranglehold on its hardware all but guarantee that the numbers won't change dramatically anytime soon.

The same is not true for the mobile market, however. Though both of those companies have mobile versions of their operating systems, neither has anything near a corner on the market — indeed, if anyone does, it's Nokia, owner of the now-Open Source Symbian platform.

When it comes to smartphone sales — the primary home of high-level mobile operating systems — Research In Motion's BlackBerry OS holds a strong lead, while Apple's iPhone has given it the runner-up position for much of the recent past. That was until Monday.

According to NPD — a research firm that tracks a number of consumer markets, including mobile phone sales, among other things — Apple's share of the mobile market is slipping this year, dropping into third place at 21%. Taking its place, just 8% behind RIM, is the darling of mobile Open Source: Android.

The numbers place Android's share of the market at 28%, giving mobile Linux — which also includes Maemo/Moblin/MeeGo and several others, for which data was not provided — more than a quarter of the smartphone market. Blackberry OS, for its part, holds a 36% share.

As NPD notes, Verizon has stepped up its efforts to match AT&T, giving both Android and Blackberry an extra push. Additionally, Apple faces a disadvantage in that the iPhone and iPod Touch are the only devices utilizing its iPhone OS, and are available exclusively from AT&T, while Android is available on two dozen or so devices across all four major U.S. carriers.

That Android's wider distribution would eventually place it ahead of Apple is little surprise. That it has overtaken the iPhone so quickly, however, is quite the achievement for a system in development less than three years, in open distribution only eighteen months, and which entered the market sixteen months after the iPhone began selling.

What it may do next — besides spreading to devices from netbooks to big screen TVs — we can only imagine.