Wirelessly posted (Mozilla/4.0 (compatible; MSIE 6.0; Windows CE; IEMobile 8.12; MSIEMobile 6.0) 480x800; XV6975; Window Mobile 6.5 Professional
AirScanner mobile has a firewall and virus scanner that I trialed a few months ago. Not free though. There are apparently very few threats targeting Windows mobile, so I removed it.