We have no official confirmation that Facetime is coming to Mac OS X and Windows, however Mac4Ever suggest that Apple is preparing an app, usually Mac4Ever rumors are usually pretty reputable.
Also See: Apple warn OS X users over security flaw
This news is backed up by the fact that FaceTime has not yet been made compatible with iChat, which is Mac OS X’s instant messaging and video chat software, many believe that compatibility would have been announced soon after the iPhone 4 launch.
Currently there are two options for Apple, they can either launch a Mac and PC Facetime app, or add support for existing instant messaging and video chat applications such as iChat, Skype, Windows Live Messenger and Google Talk.
Would you prefer a new Facetime app for Windows/Mac or support for iChat, Skype etc.