Nokia wants to buy the 52% of the Symbian operating system that it doesn’t already own to open source it and set it free.

It’s a defense against advances into the fragmented mobile space that Nokia and Symbian dominate – particularly – from the looks of case – against Google’s nascent open source Android initiative and the freebie Linux-based LiMo Foundation – but then there’s also Apple’s proprietary iPhone, Microsoft’s equally proprietary, royalty-charging Windows Mobile and the ever-present Blackberry and Palm.

Nokia is offering $410 million cash (264 million euros or $5.40 a share) for control of the 10-year-old UK-based Symbian Ltd.

It says it has already struck deals with Sony Ericsson Mobile Communications AB, Telefonaktiebolaget LM Ericsson, Panasonic Mobile Communications Company Ltd and Siemens International Holdings BV.

That gives it 91% and only leaves Samsung Electronics. Nokia figures Samsung will come around. It expects to complete the acquisition in Q4.

Nokia then intends to set up a non-profit Symbian Foundation to unite the three Symbian interface strains – Nokia’s own S60, DoCoMo’s MOAP for the 3G network and the Sony Ericsson/Moto UIQ and its Apple-like touch screen widgetry – into a single operating system with a common UI framework, which it will make available to foundation members under a royalty-free license.

LG Electronics, Motorola Samsung and Sony Ericsson – the four largest handset makers after Nokia – as well as AT&T, NTT DoCoMo, STMicroelectronics, TI and Vodafone are already in.

Nokia said it would take two years to open source the operating system under the Eclipse Public License (EPL) 1.0 with components coming out in dribs and drabs, a timeframe that could easily undercut its effort.

It said the object of the game was to “establish the most complete mobile software offering available in open source,” which must mean that Google’s Linux-based open source collective and Apple’s vision have it worried enough to launch a pre-emptive strike.

Nokia calls the foundation – which should start functioning in the first half of next year – “one of the biggest contributions to an open community ever made.”

Manufacturers are supposed to differentiate at the device level and the Symbian Foundation is supposed to simplify the platform and thereby unleash more innovation.

The only comparable efforts are Google and its Open Handset Alliance, which according to last report won’t have a phone out until Q4 at best – and a struggle at that – and the LiMo Foundation.

There are some 200 million Symbian phones out there now, representing 60% of the smartphone market (6% or 7% of all handsets), and by Nokia’s count tens of thousands of third-party applications, however impotent. 

It appears to be very much a race of who collects the most ingenious multimedia applications the fastest.

Symbian and its thousand developers will become Nokia employees once the deal is done and Nokia will save something like $250 million a year in royalties that it pays Symbian.