Thanks to a reference from a friend, I came across this website called The Story of Stuff that talks about both of these issues in a very approachable and easily digestible way (i.e. in plain English).
In a brilliantly-produced 20-minute video, Annie Leonard (who is behind the whole concept) tells us about the consumption-based system we currently live in: where it came from, why it's wrong, and what we should be doing instead. The video (which you can download from this page) is a little oversimplified, of course, but if you go to the Resources section you'll find a lot more information on limits and sustainable consumption. Leonard also writes a blog on the site, which is another really good information resource.
Anyway, since the point of the video is awareness raising, please tell as many people as you can about both the site and the video. The topics that are being discussed there are among the most important issues facing the world today and the video is definitely worth a watch.