I think I ran across this link from Raven the Maven's site. She has the best project management
blog around.

Pareto analysis is a method by which you find the 80% of the problem caused by 20% of the people, or which customers provide most the revenue, or whatever.

This Microsoft Excel tutorial is fantastic for helping you understand how to analyze and display
this sort of spreadsheet. Take a look.

Curt has a project management blog too