Also today, reference to Simmons in the NY Times, via the International Herald Tribune (no reg required):  

Is the world running out of oil? Yes and no

'We're halfway through the hydrocarbon era," my old friend Boone Pickens has been saying for the last couple of years. A folksy line like that, it sticks with you. But I hadn't realized until I began poking around the world of oil forecasting in the wake of Hurricane Katrina that it also meant Pickens had taken sides in a surprisingly heated debate. He subscribes to what is sometimes called the "peak oil hypothesis," which holds that there simply isn't very much new oil left to be found in the world. And, as a result, we are currently in the gradual process of draining the more than 1.2 trillion barrels of proven reserves that are still in the ground. And when it's gone, it's gone.

http://www.iht.com/articles/2005/09/09/yourmoney/mjoe10.php

What this does not say, and elides over, is the fact that as you slip down the other side of the peak oil curve, the energy cost of extraction increases dramatically, and you would be lucky to be able to extract half the 1.2 trillion barrels left