The gambling service, Intrade, forecast about a 33% chance that Israel or the US will attack Iran's nuclear facilities before March 2007: see Intrade
If you invest $1 you will have roughly $3 returned to you should an attack occur.
The odds here were much shorter a few weeks ago. Perhaps there has been some effect of the offer by China and the United States, made a couple of weeks back, to agree to allow Iran to use nuclear fuels provided these were enriched in Russia. The Iranians themselves have not rejected the deal but seem lukewarm towards it.
Nevertheless the gambling markets still see a reasonably high probability of action - they are forecasting the US/Israel remain reasonably likely to strike. I am interested in these types of betting markets and will watch what happens to this one as the year unfolds.
My own view is that allowing Iran to gain access to nuclear weapons would be dangerous, I do not believe that the Iranians are seeking nuclear power for energy purposes alone. If Iran possessed weapons, other fanatical Middle East regimes would follow suit. Indeed nuclear non-proliferation, globally, would likely break down completely. Then the major sources of the world's oil supplies would be subject to nuclear 'protection'. It would be a recipe for creating serious conflict.
Update: The odds might well shorten as the Iranian PM announced today that the proposal to buy enriched uranium from elsewhere would leave Iran open to limitations in supply. Iran has further indicated that it might follow North Korea and abandon the nonproliferation treaty.
American officials and the head of the International Atomic Energy Agency have said that the treaty provision allowing countries to renounce it, with 90 days' notice, constitutes a major flaw in the effort to keep nations from becoming nuclear powers. Countries can endorse the treaty then abandon it on short-term notice and began making weapons once it is abandoned.
Update: The price shortened again this morning by a couple of points as Britain's Sunday Times reported the US had drawn up firm plans to knock out Iran's nuclear facilities with deep bunker-destroying bombing raids supported by missile attacks from submarine. See here.