As Macs become more and more popular, they also become a better target for for hackers.
Sophos, a maker of anti-virus software has answered to the needs of Mac users and released a free version of their Sophos Anti-Virus for Mac Home Edition. As we type this, we are scanning our MacBook.
We don't know how many viruses currently exist for OSX, we are sure they're out there. Still, free antivirus programs are better than nothing. Sophos claims "business-grade protection," so it's worth trying out.
Have a look at the software here: Sophos for Mac