Trend Micro is the latest anti-virus company to protect against mobile phone viruses, with the launch of its new anti-virus and anti-spam software for Windows Mobile and Symbian.

Trend Micro Mobile Security version 1.0 is out today and will allow so-called "smart phone" users to download and use the software for free until June 2005. It protects against mobile threats such as the recent Skulls Trojan and Cabir worm, as well as filtering for SMS spam.

Trend Micro hopes to attract the hordes of expected new smart-phone customers this Xmas by offering the service for free until 30 June 2005, said Todd Thiemann, director of device security marketing at Trend Micro.

The product works like other anti-virus software, spotting mobile threats using signatures developed by Trend Micro. The software will protect mobile devices from new threats in "real time", as malicious code attempts to install itself on mobile devices. Users can also scan storage devices inserted into supported phones, or initiate scans of the mobile device manually.

New anti-virus and anti-spam signatures can be uploaded to the mobile device using GPRS. Alternatively, updates can be transferred using Microsoft's Activesync, he said.

Trend Micro's Mobile Security software will support a wide range of devices that run the Windows Mobile 2003 or Symbian 7.0 operating systems. A version of the product for phones running Windows Mobile, including the Motorola MPx200, O2 XPhone and Orange C500, is already available. Trend Micro plans to have a version for phones that use the Symbian operating system by January, including support for the Sony Ericsson P800, P900 and P910, and Motorola A920, A925 and A1000.

It will also release a version of the software for mobile phones and PDAs running Windows Mobile 2003 for Pocket PC-Phone Edition in January. Version 1.0 will expire in June, when the company plans to have a software update available that will add new features including firewall and data encryption features, Thiemann said.

Trend Micro is just the latest anti-virus company to offer this type of software for mobile devices. Symantec announced Client Security software for the Nokia 9500 Communicator and the 9300 smart phone model in November.

Finnish anti-virus company F-Secure also sells mobile anti-virus products for consumers and mobile operators. It covers phones using Nokia's Series 60 platform and the Nokia 9200 Communicator, as well as Pocket PCs.

Despite the attention from anti-virus companies, most experts agree that mobile phone viruses and worms are in their infancy. The first mobile phone worm, dubbed "Cabir" only appeared in June. Since then, only a handful of new malicious programs that target mobile devices have appeared, and none have spread widely. The new threats include a recent Trojan horse program dubbed "Skulls" that targets devices running Symbian.

Trend Micro has not decided on an eventual price for the software or subscription services yet.