The "PC versions" are divided into "Windows 8" and "Windows 8 Pro," a simplified structure that harkens back to the Windows XP days of two versions, Home and Professional. In contrast, Windows Vista and Windows 7 came in six editions: Home Basic, Starter Edition, Home Premium, Professional, Enterprise and Ultimate.

Windows 8, put simply, will be the version for consumers, taking the place of Windows 7 Home Premium. Windows 8 Pro -- comparable to Windows 7 Professional or Enterprise -- includes encryption, virtualization, PC management and domain connectivity features. This will be the version for tech enthusiasts and IT professionals.

(There is also a version called Windows 8 Enterprise that includes everything in Windows 8 Pro plus additional PC management tools. It will only be available for large companies to buy in bulk.)

Microsoft has not released information yet on pricing or availability for Windows 8.

Most of the features exclusive to Windows 8 Pro involve security, networking and virtualization, all technologies that IT pros use every day and need to be aware of. It's worth noting that, if you're going to upgrade, you can only upgrade to Windows 8 Pro from Windows 7 Professional or Ultimate.