NetQin Mobile Security - It is one of the best smartphone antivirus software with gorgeous interface and deep scanning virus engine. Pro members get premium support with additional features. It's light on the system with real-time shield.
ESET Mobile Security - ESET is known to deliver very efficient antivirus solutions. It's available for Windows Phone and Symbian platform. The product includes a firewall and SMS/MMS spam detection system.
F-Secure Mobile Antivirus - This excellent mobile antivirus solution is available for Android, Symbian and Windows Mobile platform. Apart from regular virus-scan engine, it also includes a system for safe web browsing to prevent opening any malicious site on your smartphone.
Kaspersky Mobile Security - It is a familiar name for million if users using the desktop version. It's mobile antivirus is available for almost all major platforms supporting wide range of mobile devices.
MobiShield Antivirus - It's a lightweight and free mobile antivirus solution with real-time shield. Although it doesn't appear that it scans the system deeply (all system files), but it’s good enough for an average user.
McAfee VirusScan Mobile - It's a comprehensive antivirus suite for smartphones protecting all entry points (mobile internet, bluetooth, WiFi) from malicious software. It is yet another mobile antivirus having an intuitive and gorgeous interface.
BullGuard Mobile Security - It's available for wide range of mobile devices and provides all-round protection from malware and viruses through deep scanning virus engine and real-time shield. Definitely worth a try.