Gap Minder is a  site that has this very cool tool that enables you to compare income distributions across a number of countries in the world between 1970-2000. Pick a few on the right side and then click the big play button and you see a view of how average incomes across the globe have changed in 30 years.  I have a feeling we're going to see this in action and it's going to be an eye-opening experience

Suggestion: Compare USA, India and China and click "play"

Thanks to Peter for the link.