Simon and Erlich agreed to bet on the price of several commodity metals. Erlich chose 5 metals: copper, chrome, nickel, tin, and tungsten. Simon bet that their prices would go down.
Julian Simon won handily.
(More details should be filled in here. this page (http://www.overpopulation.com/simon_bet.html) has a lot of detail, and presumably somewhere we could find a pro-Ehrlich page to find out if there are any additional counter-arguments.
wikipedia.org dumped 2003-03-17 with terodump