Footprint Calculator
http://www.lead.org/leadnet/footprint/default.htm
Earth Day FootPrint Calculator
A British Ecological Footprint Calculator
http://www.newscientist.com/hottopics/environment/quiz2.jsp;jsessionid=HBIDCJOJAANK
National Footprints - Trends over Time
http://www.footprintnetwork.org/gfn_sub.php?content=national_footprints
Figure 1 shows the ratio between the world's demand and the world's biocapacity in each year, and how this ratio has changed over time. Expressed in terms of "number of Earths," the biocapacity of the Earth is always 1 (represented by the horizontal blue line). This graph shows how humanity has moved from using, in net terms, about half the planet's biocapacity in 1961 to 1.2 times the biocapacity of the Earth in 2001. The global "ecological deficit" of 0.2 Earths is equal to the globe's ecological overshoot
Optimum Populaton
http://www.optimumpopulation.org/opt.ecofoot.html
New Scientist Magazine - Environment
http://www.newscientist.com/hottopics/environment/
Redefining Progress