Microsoft will launch a new version of its Windows Mobile handset platform at this week's 3GSM World Congress 2007 in Barcelona, while the exhibition itself is expected to focus more on content as the mobile industry shifts from voice-centric to more data-centric services.

Windows Mobile 6 features better integration with Microsoft's new Exchange 2007 email server; Windows Live instant messaging with presence indication; and encryption of Flash memory cards to protect data. The smartphone edition of the software gains Microsoft's Office Mobile applications.

Devices built on the new platform are expected to ship in the spring.

Handset maker HTC is also set to unveil new models at the show, including one device rumoured to have a 5in screen, qwerty keyboard and 8GB hard drive as well as HSDPA, Wi-Fi and Bluetooth connectivity. Although the device runs Windows Mobile 5.0, it could prove a tempting alternative to a laptop for mobile workers.

Another major announcement at 3GSM will be O2's decision to simplify its roaming tariffs for business travellers within Europe. The My Europe Extra scheme, launched today, means an end to charges for receiving incoming calls, while calls made from abroad will be charged at a flat rate of 25p per minute. This represents a reduction of 70 percent from existing rates, according to the mobile operator.

"Customers now know exactly how much they will get charged for both receiving and making calls while travelling," said O2's Graham Riddell.

Customers can sign up to My Europe Extra for £5 a month, or pay £10 for a one-off month. However, the scheme does not apply to data traffic such as emails and web sites accessed abroad.

"How operators justify megabit charges and pass that on to network visitors is currently very complex," said Riddell, adding that it is an issue that " needs to be sorted out".

The DotMobi registry for mobile web sites will use the event to launch a new programme designed to hasten take-up of mobile internet services. Go Mobile includes resources to help developers build better quality mobile content, and assess how well a site would display on a mobile device.