With its latest operating system, Microsoft is promising improved search, better security and tighter integration with Windows Live services.

But the operating system isn't Vista -- it's Windows Mobile 6, the latest iteration of Microsoft's software for powering mobile phones.

Microsoft plans on Monday to officially announce Windows Mobile 6, formerly code-named Crossbow, at the 3GSM trade show in Barcelona. The first devices using the software aren't expected until spring, however, with the bulk of products using the new operating system likely to come in the second half of the year.

Among the most visible changes is the ability to type in a few letters of a contact or email subject and have the phone automatically show only matching results. The software also supports HTML email. But for Exchange messages to be viewable in that form, a company also has to have Exchange 2007, the new version of Microsoft's email server software.

Windows Mobile 6 also builds in support for Windows Live instant messaging and email, which enables users to see whether a contact is online and to get their Hotmail or Windows Live Mail messages pushed down automatically.

Microsoft's software is now on many of Palm's Treo devices and also on new, slim phones such as Samsung's BlackJack and T-Mobile's Dash. The company sold three million licences of Windows Mobile last quarter, up 90 percent from a year earlier.

Because it uses the same core -- Windows CE 5 -- the new mobile operating system is expected to work with nearly all the existing Windows Mobile 5 applications.

Safe and sound
On the security front, the new Windows Mobile allows individuals and businesses to better protect their data. The phone can now protect not only data stored on the device, but also encrypt information stored on a removable memory card.

Businesses can also set policies requiring passwords to be changed regularly and also demand that they be made more complicated than "111111" or "123456".

However, neither Windows Mobile Professional nor Standard initially supports Office 2007's new file formats. That support is due to come in the summer, with a test version due out in the spring.

One of the changes that is under the hood in Windows Mobile 6, but not expected to be visible to consumers, is support for VoIP calling. Microsoft isn't including software to let individuals make such calls, but has added the internal plumbing to allow carriers and device makers to add VoIP support if they wish.