In a move that could threaten the livelihoods of security software makers Symantec and McAfee, Microsoft has announced it will offer free antivirus software some time in the second half of 2009. The free software, codenamed "Morro," will replace Microsoft's current security offering, Windows Live OneCare, a suite of services that costs consumers about $50 per year. Morro will be designed to protect PCs against viruses, malware and spyware.