The USA plans to strike at Iran’s nuclear facilities well before the latter can achieved weaponry status. Iran’s nuclear plants are well dispersed but Washington insiders claimed that American Intelligence is in possession of documents (on a laptop smuggled out) showing the whereabouts and structure of Iran’s plants.
However, the authenticity of those documents is still in doubt, as to whether they are deliberate Iranian disinformation or reliable intelligence. There is of course another Ahmad-Chalabi-sh possibility, that they're fabrications by exiled Iranians (former members of the Shah's regime) keen to see the US launch a war against the current Iranian establishment. If we remember, Ahmad Chalabi had been one such (Iraqi ) exile who fabricated and passed on to the US the intelligence on Saddam Hussein so-called WMD capability.
The Pentagon plans to strike into Iran using long range bombers like the stealth-capable B-2s and probably with submarine launched missiles. I doubt there will be any follow-up mopping action with ground troops, which if contemplated will be crazy in the light of the US Iraqi quagmire.
Iran’s air defence would not be able to counter such US strikes so we may expect Iranian retaliation in the form of terrorist strikes. The proposed air strikes will please only Israel, whose neo-con supporters in Washington are undoubtedly the principal body urging Bush to launch the attack, but the Islamic world may have a thing or two to say.
US Middle East policies have always been of Israel, by Israel and for Israel, to paraphrase Abraham Lincoln’s Gettysburg address, and rarely of, by or for its ownself.