Apple has released a new java software update that removes the most common variant of the Flashback Trojan.
From Apple security note “This update also configures the Java web plug-in to disable the automatic execution of Java applets. Users may re-enable automatic execution of Java applets using the Java Preferences application. If the Java web plug-in detects that no applets have been run for an extended period of time it will again disable Java applets.”
Source