There’s no doubt that Apple Macs and Linux PCs are far less likely to suffer from virus infections or malware when compared to their Windows cousins, but there’s also no doubt that newer technologies such as cross-platform scripting can lead to vulnerabilities across the board. Besides no-one wants to be blamed for passing on a virus infection as payload in a file, even if your computer isn’t actually infected.
Apparently “based on Sophos’s flagship security software, which protects over 100 million business users worldwide”, the software has protection, detection and disinfection capabilities for viruses and malware on OS X. It will also detect Windows viruses present in files but aren’t activated. As with most Windows anti-virus products, the Sophos Anti-Virus Home Edition runs in the background, scanning files on-access. You can read more about the technical specs and download the software here.
I’m not a Mac user, but if I was, I’d already have Anti-Virus Home Edition downloaded and installed. Yes, I know that it’s arguable that there aren’t any OS X viruses right now, but you can bet that they’re coming and when they do, the viruses will burn through the Mac community like wildfire as most people don’t have protection. It’s free to download so what have you got to lose except a few CPU cycles?