A long special report in last week's Economist on natural gas and its rapidly increasing availability. Looks like peak gas has been put off for a while yet, and, given that natural gas is increasingly substituting for oil across its usage, that may delay the inevitable for oil as well. Tough on those of us who want to see renewables advance, as all this acts to depress prices and the need for innovation. The good side to this is that gas is displacing coal in many markets (especially the USA) where carbon emissions have fallen – they're on the rise in the EU, so much scope for gloating from across the pond.
Although there's a world oil price, and the price of gas is linked to this in many places (including Europe – and how the Russians love it), this doesn't apply to gas across the board because of the difficulties of transporting it between continents, and so the price reflects regional issues. The range is eye-popping; below $3 per million btu  in the USA with its shale gas and sophisticated national gas hub – above $16 per million btu for LNG in Japan where there's no anything very much to compete with it (2012 prices).
Anyone teaching about peak oil needs to factor all this in. The Economist article is a good place to start.
Note  Quaintly, gas is measured and sold in btu (British thermal units) – a ridiculous energy unit I remember struggling with at school. A btu is ~1.056 kiloJoules. It's approximately the amount of energy needed to heat 1 pound of water from 39 to 40 °F. Madness. Just to be complete about this: 1 btu / hour is ~ 0.293 Watts. You can see how easy these numbers are. No wonder I had difficulties even though I could do percentages!