I talked with a tanker driver for HESS. He said that the press is mostly to blame because they predicted that Katrina could cause prices to rise to $5/gallon. The oil companies raised them to $3 or more and got away with it because it was short of the news media predictions. The news media opened the door for price gouging.
He said oil companies control demand by changing the gas prices. Demand is down significantly because of the high prices, so prices need to be lowered to raise demand and keep profits up.
Make no mistake, the monopolistic oil companies have more power than ever over the whole economy especially with an oil man as President.