Just as chief executive Steve Ballmer boosted Zune market share by banning his kids from owning an iPod, his company has hit on a strategy to increase use of Windows Mobile devices.

From now on, according to Silicon Valley Insider, Microsoft employees will not be able to expense mobile data plans unless they use a cellphone that runs on Windows Mobile software.

That means the Apple iPhone, Palm Pre or any RIM BlackBerry are out, among other models.

A rep for Microsoft confirmed the story was true, and said the move was part of the company’s recently announced cost-cutting plan.

Although Microsofties can no longer use phones that run on rivals’ software - a surprisingly liberal policy to begin with - employees at recently-acquired subsidiaries, such as online ad company Razerfish - can still use any handset they like.

In New Zealand, it doesn’t seem any ideological, fiscal or technological realignment is required. NBR has yet to meet a Microsoft NZ staffer not using a Windows Mobile handset.

A Microsoft spokeswoman explanins: “The majority of eligible New Zealand employees are part of a corporate plan using company owned phones. This plan varies depending on the employees’ role and their use of broadband and cell phone minutes. A small number of employee’s choose to use a handset that is not a company asset and are currently still eligible to claim the acceptable amount for phone use related to business activity.”

Handsets running Microsoft OS include the Motorola Q, numerous models from Taiwan’s HTC and, on Telecom’s network, the Palm Pro.

Melinda Gates

Of course, rules are made to be broken, and forbidden fruit can be tempting.

Echoing Microsoft chief executive Steve Ballmer's infamous 2006 comment to Fortune that he wouldn't let his kids have an iPod, Bill Gates' wife Melinda recently told Vogue that "There are very few things that are on the banned list in our household. But iPods and iPhones are two things we don't get for our kids.

"[But] every now and then I look at my friends and say, 'Ooh, I wouldn't mind having that iPhone,' " Ms Gates (pictured) told the magazine.

And, of course, there's nothing to stop any Microsoftie from yielding to Apple's temptation. Just don't try to expense any data.