The most interesting aspect of Sony Ericsson's recent decision to release the Xperia X1 - a Windows Mobile-enabled handset - is that it leaves Nokia somewhat in the cold.

The Finnish company is now the only major mobile manufacturer not to offer Microsoft's Windows Mobile OS as an option - aside from Apple, of course. So is Sony Ericsson really harpooning its trusty Symbian software? No, of course not. But it does mean that Sony Ericsson now sees Windows Mobile as an OS that's finally going places.

Windows Mobile: a slow starter

Sooner or later, Windows Mobile will have the features that will make it stand out from the pack. At the moment, it runs like a dog with three legs, but it's pretty clear that this will change. As any Microsoft watcher will realise, Redmond needs several bites of the cherry before it gets something right. Or as near to 'right' as it can.

Crucially, Microsoft can't waste any more time, not with the immediate threats to its operating system posed by Apple's iPhone and Google's forthcoming Android platform. Microsoft also knows that natural, intuitive interfaces will be a big focus over the coming years and it seems determined to meet that challenge head-on.

John Starkweather, director of international marketing for Windows Mobile, told us at Mobile World Congress that the Sony Ericsson deal is part of Microsoft "broadening the appeal [of Windows Live] to the consumer."

Will Nokia kiss up to Microsoft?

So what's going on with Nokia? Nokia's president and CEO Olli-Pekka Kallasvuo gave a clear "no current plans" when asked whether the company had a Windows Mobile-powered phone in the pipeline. That's not to say it won't do one in the future. But it certainly wouldn't seem to be in the company's current thinking.

Despite popular opinion, Microsoft and Nokia seem to like each other. They're already in partnership in several areas including Microsoft's PlayReady and Windows Live. Sony Ericsson won't be turning its back on Symbian - it part owns the company and the OS has proved its worth in the lower-end CyberShot and Walkman phones.