A couple of links that might be worth a look for those interested.
A population clock. Shows the estimated population of the world. Counting constantly and has a window to compare to what the world population was back as far as 1970.
http://www.ibiblio.org/lunarbin/worldpop/index.html
The 'footprint calculator' a resource used in schools promoting sustainability and ideas of how to reduce ones consumption of the world resources.
http://www.epa.vic.gov.au/Eco-footprint/
The world population went up about 1000 people while I was finding these web links and typing this reply!!
SN