Apple has posted a Knowledge Base article that addresses the recent MacDefender malware issue and also reveals they will be addressing it in the next few days through a software update
In the coming days, Apple will deliver a Mac OS X software update that will automatically find and remove Mac Defender malware and its known variants. The update will also help protect users by providing an explicit warning if they download this malware.
Article Link: Apple to Update Mac OS X to Remove 'Mac Defender' Malware