Nokia has revealed that it plans to work with Microsoft, using the Windows Phone operating system as its 'primary smartphone strategy'.

In an open letter to Steve Ballmer, Microsoft's CEO, Stephen Elop spoke of mutual benefits, and how Nokia will help Microsoft in areas such as mobile imaging.

The letter also talks about how the Finnish company will help "drive and define the future of Windows Phone" with a nod to widening the range of price points suggesting a budget Windows Phone from Nokia is on the way.

Search and apps

Bing will now be the default search engine on Nokia handsets across devices, suggesting it's a partnership that stretches beyond Nokia manufacturing Windows Phone handsets.

Nokia's app stores will also be integrated with Microsoft Marketplace, presumably incorporating the Ovi Store and all its content.

Echoing thoughts in his memo to staff which leaked earlier in the week, Elop notes that, "Success requires speed. We will be swift."

But will they be swift enough to reveal a new Nokia Windows Phone handset at Mobile World Congress?

Disruption

Elop ended the letter saying, "Today, the battle is moving from one of mobile devices to one of mobile ecosystems, and our strengths here will be complementary.

"There are other mobile ecosystems. We will disrupt them."