Already, a trojan horse virus has been let out on Leopard. But trojans are the least effective uses of a virus, because it needs the users' log in name and password to be entered. The virus appeared on some pornography sites. There is a still frame picture of the movie, and clicking on it brings you to a page that says you need a new version of a codec and needs you to download it. Then the user needs to enter their password and it starts messing with their system. Doing the normal virus stuff.