By Jim Reed
Newsbeat technology reporter
"Open source" software means anyone can access the code for free
Nokia is taking control of a British company called Symbian that develops the software that runs its mobile phones.
It is paying a number of other electronics companies £209m to buy out their stakes in the business.
But it is what Nokia wants to do next that makes the deal interesting.
The plan is to offer Symbian for free to any developer or mobile phone company that wants it.
That decision could make a big difference to the way we all use mobile phones in the future.
What does Symbian do?
If you use a PC at work or home, the chances are you are using Microsoft Windows.
But the market for mobile phones is more open with a bunch of different operating systems used on different handsets.
Symbian is already used in six out of every ten smartphones including models from Nokia, Sony Ericsson and Motorola.
But it is overshadowed in the important American market where rival RIM, maker of the Blackberry, dominates.
New platforms from Apple and Google are threatening to take market share away from Symbian.
What's this about free software?
Nokia is taking all £400m of Symbian's assets and putting the whole lot in a not-for-profit foundation.
Nokia will be hoping that Symbian ends up dominating the market
The software will be "open source", meaning that anyone can access the underlying code for free.
Independent developers will be able to make new mobile applications without paying a fee.
And phone makers that sign up to Nokia's "Symbian Foundation" can use the operating system without a license.
Why should I care?
Think of a mobile map showing where all your friends are at any one time.
Or interactive video that lets you keep an eye on your house when you are away on holiday.
Independent software companies are keen to develop these kinds of applications for the latest, high powered phones.
Those programmes will run on top of an operating system in the same way that Excel, for example, runs on Microsoft Windows today.
So the battle for control of your mobile is now underway with firms like Nokia, RIM, Apple, Microsoft and Google all trying to create the next "wireless Windows".
What's in this for Nokia?
Nokia is giving Symbian away in the hope that other phone makers will jump on the bandwagon and use the same operating system.
That should make the platform more attractive to independent software developers and, Nokia hopes, lead to a snowball effect where Symbian dominates the market.
That control should let it develop new phones more quickly and increase sales in the longer term.
Nokia does not want to be in a situation where it is forced to use an operating system supplied by one of its competitors.
What's this about Android?
Nokia and Symbian are far from the only game in town.
Competing with Symbian is Android which sports touchscreen
Google has been working on its own operating system for mobile phones called Android.
The software is open source and free in the same way as Symbian.
The latest prototypes feature a touchscreen-type interface that looks more than a little like Apple's iPhone.
The first mobiles with Android built in are expected to hit the shelves before the end of the year.
Some reports suggest the project is facing delays and technical problems, something Google has denied.
Who else is part of this battle?
Where to begin.
The other major contenders include Microsoft with its Windows Mobile platform and Apple with the iPhone.
That office favourite, the Blackberry, runs on software developed by its owner, Canadian company RIM.
Another open source project, called LiMo, is backed by a group of mobile phone companies including Motorola, Panasonic and Samsung.
It is all to play for over the next couple of years.