There is a Trojan horse that is targeting OSX that was found on some free porn sites. Pretty much go to a free porn site that requires you to download a codec to view the porn and it installs a trojan horse instead. After downloading the codec you are required to enter your root password which then grants the virus full access to your computer. So those foolishly thinking that macs are virus free, think again. Unfortunately, with more people buying macs more viruses will be written for the OS. Read here for more details.