Do you feel this new reserve currency posses a threat to the dollar?
Yes it is, because of the fact that the Euro is widely enough to be a viable alternative to the dollar. If Iran did open its oil bourse, I don't think that would be enough to make the dollar collapse. It's pretty hard to predict what the Fed Reserve is going to do. In fact, I have heard that in March, the Fed is going to stop publishing information on the M-3 supply.

Do you feel this event has any bearing on the adminstration's posture towards Iran?
I don't think so. Europe seems to be getting angry at Iran as well. So in this case, it really may be about the WMDs and not the oil or the dollar issue.
Also, there were UN sanctions on Iraq prior to 2003, essentially crippling trade with Iraq. So Saddam Hussein dumping his dollars is probably a mute point.

Well, then, you may say, surely the international role of the dollar forces people out there to hold dollars for transaction purposes. Yes, but not so you'd notice. When Daewoo repays a dollar loan from Sanwa, it writes a check on its account with some international bank. True, that bank itself surely maintains an account in New York, backed in part by non-interest-bearing reserves held at the Fed. So the U.S. does in effect get a zero-interest loan out of the dollar's international role--but it probably amounts to only a few billion dollars, small change for an $8 trillion economy.
 

Where the U.S. does get a significant free ride is from the willingness of foreigners to accept our currency--actual bills. Foreigners hold more than $200 billion of American money. Guess what kind of business requires payments of large sums in cash, by people unconstrained by official restrictions on possession of foreign exchange? That's right: the dollar is the world's premier medium of illicit exchange. Every year the U.S. ships foreigners $15 billion in cash (about 0.2% of GDP), and gets real goods and services in return. Better not ask what kind.
 

So the threat to the U.S. from the rise of the euro is this: five years from now, when wise guys in Vladivostok make offers you can't refuse, the payoffs may be in 100- euro notes instead of $100 bills. The loss of such business might cost the U.S. economy as much as 0.1% of GDP. Somehow, I think we can live with that.

I don't know much about what Iran is planning (nor does a Google search yield much trustworthy information), but this fear is based on faulty economics.  As a first-order approximation, it doesn't much matter whether Iran prices its oil in terms of dollars, Euros, or some other currency.  At the beginning of each day, investors (including the OPEC nations) are holding their preferred bundle of currency positions.  You might need to hold or receive Euros for a moment to make a transaction, but moving from the dollar to the Euro, or vice versa, can be done easily.

Two qualifiers: First, some investors will hold more Euros to begin with.  They don't know their periodic demands for oil, and they don't want to be bothered paying a bid-ask spread and calling a broker when the time comes to pay for oil.  But this is likely to be a small effect.  Major market players generally do not regard these conversion costs as a decisive investment factor.  Bid-ask spreads in the dollar-Euro market are small, and if the dollar fell by a large amount it would be worth buying dollars cheaply and bearing subsequent transactions costs of a later reconversion at a superior rate.

Second, the dollar's status as reserve currency depends in part on perceptions.  If pricing oil in terms of Euros altered those perceptions, the value of the dollar could fall.  But most of all those perceptions depend on relative economic performance.  An Iranian "oil bourse" is likely to be. in psychological terms, a non-event, especially if Iran continues down its path as international pariah.  Note that Saddam's efforts to price oil in terms of Euros did not end up as a big deal.