T-Mobile has announced the availability of a push email service for customers using its Windows Mobile 5.0 handsets. The service is available for companies running Microsoft's Exchange Server 2003 and offers a flat-rate tariff to simplify billing for firms.

Microsoft Push Email from T-Mobile is available immediately under the operator's Web‘n’walk Professional tariff, which launched in May for laptop users with a datacard. This offers unlimited data access, subject to a fair use policy, for £17 per month for data-only or £8.50 per month on top of a voice tariff. T-Mobile defines fair use as up to 2GB of data traffic per month

Jote Bassi, marketing manager for data at T-Mobile, said the service is an alternative to BlackBerry for customers that prefer a Microsoft-based system. " The differentiator is that it's a simple tariff, offering predictable pricing each month, and works on a range of devices," he added.

The service will be available across all of T-Mobile's Windows Mobile 5.0 handsets, including its MDA Pro, MDA Vario and MDA Compact, and also works over GPRS, 3G and Wi-Fi connections. It does not require any third-party infrastructure.

"We already sell these Microsoft devices, but push email turns them into an indispensable tool for business," said Bassi, adding that the new service turns the MDA into a “mini laptop”.

Companies will need to have an email system based on Exchange Server 2003 with Service Pack 2 to make use of the service. This version of Microsoft's groupware server added support for push delivery of emails, along with the ability for administrators to remotely wipe a lost or stolen handset and enforce keypad lock settings on company devices.

T-Mobile plans to extend the Microsoft Push Email service to include Nokia's E61 enterprise handset, plus other phones that are not Windows-based but which are compatible with Microsoft's ActiveSync protocol, according to Bassi.

"Email will be ubiquitous in the future. It will be up you to choose which tariff and device best suits you," Bassi said.