I think MAH is absolutely right that Iran is next in the sights of the US. Statements out of Cheney and Bolton in the last week are probably meant to try one last time to push Iran to voluntarily give up its nuclear weapons program. At the same time, there was a story on Sunday
that the US was refusing to join the EU diplomatic drive against Iran, another move intended to pressure Iran. There are also rumors that Air Tasking Orders (the orders for what kind of planes, what ordnance, and what flight routes are to be used for an attack) have been issued by the Pentagon to units in the area.
The question then is who would actually execute the airstrikes against Iranian facilities and how, assuming that John Pike is right and Iran's facilities are above ground and we know where the vast majority of them are. It seems to me that it is not in either Israel's or the US's interest to have Israel destroy those facilities. First, the routes that Israeli planes would need to fly would be either through Saudi Arabia (an unwelcome prospect even with Saudi Arabia's concern about Iranian nukes), or through US controlled airspace. In any case, the US would be blamed for bombing Iran's facilities. Why take the blame, without getting any of the credit?
Second, and Israeli strike on Iran could cause a much wider regional confrontation. Iran will undoubtedly want to retaliate against Israel for such an attack. It could launch its Shihab-3 ballistic missiles at Israel, though it seems from some reports that those missiles are not fully operational yet. More likely, Iran will activate Hizbullah to fire missiles at Israel. Given the number of missiles that Hizbullah has been given by Iran and Syria, and and the range of those missiles - some able to reach the center of Israel - Israel will have no choice but to respond. The response would need to be a full-scale multi-divisional assault on Hizbullah-land in the south of Lebanon, and would then potentially put Israel in confrontation with Syria. Clearly, this scenario is not one that either Israel or the US wants.
So, barring a revolution in Iran, it seems that unless the US can pressure Iran into completely giving up its nuclear weapons pursuit, the US will need to carry out airstrikes on the Iranian facilities. Hopefully this will spur reformist elements in Iran to rise up and overthrow the mullahs.