As Tommy said in his writeup in dump the pump, the higher prices for petrol have not cured the world of increased demand for what is ultimately (as the current thinking goes) a non-renewable natural resource.
In the long term, the only cure for high prices is high prices. Only a high price will eventually encourage the market from the bottom up to move towards more fuel efficient cars, better use of available oil and the development of alternative sources of energy. Note that it was during the last oil shock of the 1970s that super petrol guzzling cars went out of fashion in the U.S. and that the developed world moved towards being less dependent on crude oil supplies from the Middle East.
The reality of the current situation is that the raised price of crude oil from US$10/barrel in 1998 to US$35/barrel recently have still not caused any significant drop in demand (demand is in fact rising from Asia as it recovers from the Asian Financial Crisis of 1998-1999).
Attempting to cut down the price of crude oil by pumping more oil is about as good as pushing on a string.
Personally, I think that the protestors against the high price of petrol are just as misguided as the protestors currently at the World Economic Forum in Melbourne - both protests have almost no chance of success and are causing a lot of damage to innocent bystanders.