We've known for a while that Microsoft is offering some upgrade promotions for its new OS, but the company has now said that it will be selling Windows 8 Pro upgrades online for $39.99. In stores, the price will be quite a bit higher: $69.99. The offer is eligible to anyone currently running any version of Windows XP, Windows Vista, or Windows 7; it will last until January 31st, 2013. That's the same time frame offered for the current $14.99 upgrade deal, but it applies to any current Windows users, not just those who purchase a new PC in the lead-up to Windows 8's launch. Microsoft says the offer will be available in 131 markets, and that it will release more details as we get closer to launch.

We've also got some more details on the upgrade process for older versions of Windows. An upgrade assistant will help users migrate files, settings, and apps from Windows 7, files and settings from Windows Vista, and files only from Windows XP. As before. After the upgrade, you can add Windows Media Center for free through the “add features” option. The online version obviously comes as a download, but it's possible to buy a backup DVD for $15. Users who aren't upgrading from a previous version and are building their own machine or running a virtual one will need to buy Windows 8 Pro System Builder. Microsoft generally offers upgrade deals for its early adopters, but this is both cheaper and more widely available than the equivalent option for Windows 7.