All good things must come to an end. Macs have become the targets of more virus and malware attacks recently. PCs currently endure the majority of attacks but Macs are not as immune as they once were. Fortunately, if you're a Mac user like I am, anti-virus products are available to help protect against possible cyber threats.
From Security News Daily - Top 10 Mac A/V programs
From ZDNet - Apple's internal memo regarding MacDefender malware and how their customer service should respond to users.