While Apple has said it "is developing software that will detect and remove the Flashback malware" that has affected up to 600,000 Macs worldwide, it has yet to release any fix. In lieu of that a few security and antivirus firms have gone ahead and released their own Flashback removal tools.
Kaspersky Lab, a Russian antivirus firm, has released the Flashfake Removal Tool. The firm asks that you first check here to see if your Mac is infected with Flashback. If your Mac is, then you can download Flashfake to rid your Mac of the malware.
A second antivirus firm, F-Secure, has also released their own Flashback Removal Tool. Their tool works by creating "a log file (RemoveFlashback.log) on current user's Desktop. If any infections are found, they are quarantined into an encrypted ZIP file (flashback_quarantine.zip) to the current user's Home folder. The ZIP is encrypted with the password 'infected.'"
Before Kasperky Lab's and F-Secure's removal tools, users had to manually remove the malware by using OS X's Terminal, which some might have found confusing.
There's no word from Apple yet on when their own removal tool will become available.