Though it isn't free.

"F-Secure extends antivirus to Windows Mobile
Company also releases new product with mobile firewall, antivirus for Symbian Series 80 users

The company also released another new product, Mobile Security, that has a mobile firewall and antivirus protection for Symbian Series 80 users.

Mobile Antivirus is delivered to subscribers wirelessly and provides real-time protection against viruses, worms, and Trojan horses. It will cover Windows Mobile 2003/2003SE Pocket PCs Phone Media edition including devices such as the Qtek 9090, MDA III, Qtek 2020, Qtek S100, MDA Compact and T-Mobile branded ones such as MDA II, MDA III and MDA Compact, F-Secure

Support for the Windows 2003/2000SE Smartphones Edition includes devices such as the Motorola (Profile, Products, Articles) MPX220, Qtek 8200, Qtek 8010, Qtek 8020, SDA, Qtek 8100 and SDA Music, the company said.

Mobile Antivirus for Mobile Windows is available for download from F-Secure and costs $34.95 for a 12-month subscription, Vihavainen said.

Source

Hendrixus