Microsoft is unlikely to launch a Zune phone to take on Apple's iPhone, according to Jupiter Research analyst, Michael Gartenberg.

Ballmer last week said he planned to ramp up his battle with Apple, saying the company plans to change the way it works with hardware vendors in order that Microsoft Windows solutions can compete properly with Apple's superior products.

"Today, we're changing the way we work with hardware vendors to ensure that we can provide complete experiences with absolutely no compromises. We'll do the same with phones - providing choice as we work to create great end-to-end experiences," he said.

Microsoft Zune review

Apple iPhone 3G review

That's a huge change in the way the company works with its partners - and may take a while to actually percolate into products, most believe.

But one of these products won't be a phone - well, not a Zune phone at any rate. Jupiter Research analyst, Michael Gartenberg points out that there's a difference between the business models of Windows Mobile (Microsoft's hope in the mobile phone space) and Zune.

"Windows Mobile is a core platform and OS. No one has ever been successful licensing technology platforms to others and then competing with a device of their own. Apple failed (twice), Palm and Nokia all tried it and it just can't be done," he says, observing that 20 million Windows Mobile licences have been deployed.

The analyst thinks Microsoft's most likely to put mobile Zune-branded functions inside future version of Windows Mobile, in a similar way to the inclusion of iPod features within the iPhone.