On this page will be listed general purpose, high-quality, and possibly non-commercial, advertising-free web sites.
http://www.greenfacts.org/ has a series of very clear and informative summaries of scientific reports. Their "Mission is to bring complex scientific reports on health and the environment to the reach of non-specialists."
http://www.footprintnetwork.org/ Global Footprint Network's vision is to make the Ecological Footprint as prominent a metric as the Gross Domestic Product (GDP).
http://paulchefurka.ca/ A personal web site, with many must-read articles with in-depth analysis on population, energy, overshoot, etc.