This is a very good webpage, written and developed by a science professor for his students, but which is a very good primer for the many who don't know of peak oil at all. It can also be used as a great refresher for those of us who do know; it never hurts to read through some of these things again and strengthen one's knowledge. I especially liked how he tackled it from a somewhat different perspective of population dynamics (the warmup consists of a lot of examples surrounding "overshoot:", when a population exceeds the carrying capacity of its environment), rather than approaching it from an environmental or economic perspective as most PO-aware often do. Warning: it is quite long, and contains many video links, so this will take awhile.
So this joins the short list of PO materials and media that I'd recommend to the PO beginner. Others include Kunstler's book "The Long Emergency" and the documentaries "The End of Suburbia" and "Collapse". I'd say that this is the most gentle and least doomerish of the lot, so it's recommended for the especially squeamish.