Below is a simple guide to the three versions of Microsoft's newest operating system, Windows 8. I wrote this overview for my friend's parents, so I've tried to make the language as simple as possible. Enjoy!
Windows Phone 8
This is Windows for mobile phones.
The screen is filled with "tiles" that can launch apps (programs). Many of these tiles will display live information, such as updates from Facebook. Windows Phone 8 does not have a desktop view (such as the view you have on your computer) and will only run apps (programs) made for Windows Phone 8. Your computer programs will not run on this phone. You can add new apps (programs) through the store that comes installed on the phone.
Windows 8 RT
The view is nearly identical to Windows Phone 8 and there is no desktop view. While there are a number of manufacturers making Windows 8 RT devices, Microsoft is selling their own tablet called the Surface. Windows will preinstall the basic Microsoft Office programs with Windows RT. Additional apps (programs) can be added to Windows 8 RT through the Store included on the device. Windows RT cannot run standard Windowds (non-RT) programs.
Windows 8 Pro
This is the robust Windows experience.
The primary view in Windows 8 Pro is the same as the "Modern UI" tiled view seen in Windows Phone 8 and Windows RT. However, you can also move into a desktop view that is nearly the same interface as the one you are used to seeing on Windows. Windows 8 Pro can run both your traditional programs, as well as the new Windows 8 applications.
Many manufacturers are making Windows 8 Pro tablets, laptops and PCs. Microsoft is also making their own Windows 8 Pro tablet, the Surface Pro.