Cruise Missiles, GPS guided smart bombs from stealth aircraft, special ops forces with explosives, snipers (not that I think we'd need snipers).
Our military is built for two things:
1) Big, sloppy destruction
2) Small, precision destruction
The latter is what we'd use in Iran. It would be a surgical strike in a few choice locations to eliminate facilities and get the message across "diplomatically". The most difficult thing for our military to do is occupy territory, but I don't think we'd need to do any of that in Iran.