"This is a good day. I am super happy," Jim Allchin, co-president of Microsoft's Platform Products and Services Group, said in a conference call with journalists and analysts this afternoon.

The RTM version is the first step toward the widespread availability of the operating system, which is slated to be available to corporate volume license customers via the Web or on CD sometime before Nov. 30, and to general consumers on Jan. 30, 2007.

PC makers, said Allchin, are getting copies of the Vista RTM immediately. "We are giving it out as fast as we can," he said.

Nevertheless, consumers and small businesses will not be able to buy PCs with Vista preinstalled from stores or small OEMs before the Jan. 30 launch date, he said.

Vista is also not yet available for consumer download, although Microsoft has said that it will be available to MSDN and TechNet subscribers some time this month.