Checkout Gapminder, a pretty cool tool from Google (still in beta).
Gapminder is a non-profit venture that develops information technology for provision of free statistics in new visual and animated ways. In short, it enables you to make sense of the world by having fun with statistics.
Currently the tool allows simultaneous comparison of two statistics (out of about 15) of all countries, or specfic countries and even animates the change in values from 1975 to 2005. Surely, as more statistics will be added, has potential to be very useful---looks like yet another cool tool from Google.