Mac Trojan Set Loose—More to Come?:
"The first malicious Trojan for Mac OS X has been found in the wild, leading some to claim the platform may be on the verge of increased attention from virus writers."

The Trojan—dubbed AS.MW2004.Trojan by anti-virus company Intego—was first discovered by a reader of British Mac magazine MacWorld. It takes the form of a file purporting to be a version of the newly released Office 2004 for Mac and is available on download services such as LimeWire.

However, despite appearing with a legitimate-looking icon, the Trojan is in fact a simple AppleScript application that, when run, erases the contents of the user's Home folder. And, unlike the real release of Office 2004, the application is only 108KB in size.…

http://www.eweek.com/article2/0,1759,1591850,00.asp?kc=ewnws051304dtx1k0000599