I think we should stop *****-footing around the issue with all the diplospeak. The US embassy in Iran should deliver to the Iranien state department a note that says, in full "You have one month to knock it off: No more uranium enrichment, no more funding Hezbollah. If you don't, the embassy will be withdrawn, and we'll take matters into our own hands. One month." After a month, if Iran has not responded, the US should immediately launch it's attack.
First, every major radar installation around their country get hit as quickly as possible. B-2's and F-117's will likely have to handle this stage completely. (We have a total of about 80 of those planes, even if we leave a few in reserve that is enough to launch a coordinated assault over quite a large area) And no, our current operations in Iraq would not hinder the following effort, as what we are doing in Iraq requires ground troops; my plant only requires massive amounts of airpower - something we thankfully have a great deal of. After their radar net is almost entirely down, then the bombing run of their nuclear installation begins. Those we think we can destroy with bunker-busting weapons we destroy that way; the installations that we can't reach using bunker-busters we take out of commission the way they used to take out castles to costly to takse: by siege. Only we do it by air, namely by flattening every possible entrance to the installations above ground for, say, 10-20k in every direction. (Most of the installations are at least that far away from major population centers) They may have tunnels 20+ kilometers long, but I doubt it.
After that, if Iran still won't agree to stop it's nuclear weapons program, I propose we begin effectively decapitating their nuclear weapons research and military strategists. I'm sure between the Israeli's and the CIA we have a pretty good idea where most of them live when they're not in the thick of things - so once we're reasonably sure that they're back home, we flatten their houses with bombs.
After more time of this, either Iran will eventually weary of it all, or we move on to the rest of their military and other important buildings and objects, such as major transportation routes and airstripes. Either they'll crack, or we can stop after a few months with their military and atomic program in pieces; their call. Additionally, I suppose we should send a letter to Damascus, something along the lines of "Play ball with the Israeli's, and stop funding Hezbollah, or you're target #2."
I suppose I should stop dreaming, though - no one seems to have a spine these days, except the Iranian clerics.