The following are few of the linux based antivirus software that are free for personal use
Panda AV http://www.pandasoftware.com/download/linux/linux.asp
BitDefender AV is the only software with a GUI version and integrates into the desktop environment (Start menu, right click menu ..). It can run continuously in the background similar to windows antivirus software. It also has the antispam module built in and integrates with other useful applications.
ClamAV also has 3rd party GUI interfaces like ClamTk (http://clamtk.sourceforge.net/)
Labels: free antivirus software, linux