We just added a page in the PowerPivot Workshop web site containing an introduction to PowerPivot. There are already several web sites with a general description of PowerPivot and we adapted parts of the first chapter of the book PowerPivot for Excel 2010: Give Your Data Meaning. The goal is to give a step-by-step explanation to people who use PowerPivot for the first time and want to understand the difference between a PivotTable based on Excel data and a PivotTable based on PowerPivot.
I hope this will help PowerPivot newcomers and also BI consultant that have to explain what is PowerPivot to regular Excel users.
And remember the next two dates of our roadshow in Europe (other dates will be announced soon):