Apple's Flashback malware removal tool will remove the most common variants of the Flashback malware. This update is recommended for all OS X 10.7 Lion users without Java installed.
If the Flashback malware is found, a dialog will be presented notifying the user that malware was removed.
In some cases, the Flashback malware removal tool may need to restart your computer in order to completely remove the Flashback malware.
See this Apple Support article for more details about this update.