The Bush administration will never allow the Iranian government to open an exchange where oil can be traded in euros. If that happened, hundreds of billions of dollars would in turn submerge the United States, collapsing the dollar and thus destroying its economy. This is why "Bush and Co" plan to lead the nation to war with Iran. It is simply to protect the current system of globalization and the continued dominance of the dollar as a reserve currency.
The complaint that Iran is developing nuclear weapons is nothing more than a pretext to start war. The NIE (National Intelligence Estimate) predicts that Iran will not be able to produce nuclear weapons for perhaps ten years. Much like IAEA chief Mohamed ElBaradei has said over and over again that his agency's inspectors have found "no evidence" of a nuclear weapons program.
There are no nuclear weapons or nuclear weapons programs, but Iran's economic plan poses an existential threat to the United States.
The US monopolizes the oil market. It is valued in dollars and is traded either on the NYMEX (New York Mercantile Exchange) or on the IPE (London International Petroleum Exchange) both belonging to the United States. This forces all central banks around the world to maintain huge stocks of dollars.
The monopoly of the US currency perfectly illustrates the pyramid scheme. As long as nations are compelled to buy oil in dollars, the US can continue to waste outrageously with impunity. (The dollar now represents 68% of the world's capital currency against 51% ten years ago) The only threat to this strategy is the competition that an independent oil market would project; thus forcing the faltering dollar to confront a more stable (debt-free) currency such as the euro. This would force central banks to diversify their assets, sending billions of dollars back to the US, thereby guaranteeing us a devastating cycle of hyperinflation.