You can't use Windows based programs on a Mac without emulation software.
I've never tried AV software running under an emulator but I seriously doubt it will work based on the Windows registry hive, drive structure and other factors that most Windows based AV software looks through and requires to run.
Norton and McAfee both do a version of their software for the Mac.
click here for some information on the Apple UK site on the McAfee product called Virex, and click here for the Mac version of Norton Utilities.
click here for general links leading to a variety of AV software for the Mac.
There are lots of products available and a quick look on the Apple and Symantec websites will give you some ideas.