Peak Oil is here.

Peak oil is a relatively complicated notion. What it essentially means is that the global production capacity has peaked.

Oil "reserves" vary in value: obviously there is size, but there is also the "sweetness" of the oil, which is how easy it is to process, and how easy it is to access, based on its depth as well as the political situation around it (like say, a bunch of crazies like Nigeria).

So that doesn't mean we're out of oil. The supply/production has peaked, but demand will continue to go up, especially as 2.5 billion people in India and China gradually industrialize/modernize. Thus the price of oil will go up.

This will cause several interesting results:

1) Offshore/outsourced production will decline, since it will be cheaper to make things locally rather than ship them across the ocean from China/Malaysia/whereever. This will stunt India and China's growth.
2) At somewhere around $80-100/barrel, a host of alternative energy schemes become price competitive. Which will drive research and economies of scale in those schemes, and move energy generation from oil to those techonologies.
3) Inflation may strike if the oil price increases are not carefully managed by the government. The stagflation of the 1970s was a similar situation, and America's overall financial health due to high debt loads is more precarious now.
4) Something will have to be done about the SUVs on the road. A heavy gas guzzler tax on existing inefficient consumer cars will be imposed. If they aren't all bankrupt by then, the Detroit automakers will be further screwed since the Japanese are so far ahead on efficient vehicle design.