Microsoft is reportedly about to start field tests of Windows XP working on the $100 XO laptop from One Laptop Per Child in 2008.

Although the software giant has not committed to the project on the XO laptop, if the trial is successful it will release the operating system in the first half of 2008.

Microsoft's James Utzschneider, writing on his blog, said: "We are hard at work on the project here".

Going on to comment how the port and process of getting the software working on the PC is "unusual" for Microsoft.

"We are managing the entire process of adapting and testing an existing version of Windows for a new PC. Usually the hardware vendor does this. And the Windows port to the XO is by no means done. Between Microsoft employees and third party contractors that we have brought into the effort, we have over 40 engineers working full-time on the port."

If the operating system was to be successfully ported to the laptop it would likely be a massive boost for the project.

According to the BBC, there have been reports that some countries have been cautious about signing-up to the project because it does not run Windows, the world's most popular operating system.

However Utzschneider warns:

"We [Microsoft] have not announced formal plans to support the XO yet, and we will not do so until after we start getting feedback from our first limited field trials starting in January before we make the final call."

"In fact, you should not yet assume that Windows on the XO is a done deal. We are hopeful that we will have a different story for you within 6 months."

Finally commenting that the non-announcement also means "that if you are in the US and Canada and are participating in the Give One Get One program, you need to understand that Microsoft is not currently planning to support a retail consumer release of Windows XP on your XO computer".

We will keep you posted.