Ummm guys, I'd better fill in the blanks here....
As Beagle said, one of the best defences against malware attacks on the Mac is to ensure that your admin account is password protected and that you always operate from a user account for day-to-day use.
And just before the Windows users get their knickers in a twist: "No, the Mac is not immune from malware."
- Mac Defender is a real anti-virus program made for Mac users who don't assume that the Mac is "untouchable": http://macdefender.org/index.html
- Some shitbags have come along and created a trojan (not a virus) and called it "Mac Defender"
- They've used search engine optimisation techniques to climb the Google rankings, to increase the chances that Mac users who are looking for anti-virus software will mistakenly download the trojan
- The unsuspecting Mac user provides an admin-level username and password to permit installation of their new "anti-virus program"
- The trojan pretends to have found "viruses" on the host Mac, and asks the user to give credit card details in exchange for "curing the problem"
- Some poor, naive sods then give their credit card details to the aforementioned shitbags...
As Beagle said, one of the best defences against malware attacks on the Mac is to ensure that your admin account is password protected and that you always operate from a user account for day-to-day use.
And just before the Windows users get their knickers in a twist: "No, the Mac is not immune from malware."