Andre has made a comprehensive update to our Windows 8 FAQ. This 75+ question FAQ covers all Windows 8 topics, both technical and non-technical. This document is a great starting point to get up-to-date on the new OS. Here is an excerpt:

Q: What is the Charm and App Bar?

A: Within the Start Screen interface are some hidden features that are more Touch ready and available when using on a Tablet. If you are working with a mouse though, you can discover some of them to make working in the new interface easier. For instance, if you right click a traditional desktop application this brings up a Charm bar, a feature that lets you do simple task such as unpin a tile or access advanced task such as pinning to the Windows Taskbar, Run as Administrator or navigate to the file location. The Charm Bar gives quick access to system settings along with the ability to share information between your applications.