Don't forget Syria.
Completely close the borders. Encourage dissension. Arm and train dissidents. Massive communications and propaganda effort - e.g. the mullahs have outlawed satellite dishes so send in alternatives. Economic pressure on Iran and its trading partners. Sabotage. Provoke an armed confrontation.
What I wouldn't do is what the US has done so far - jaw jaw in the UN.
Provoke a confrontation? You mean war, right? We'll have to disagree about what was the greater danger. You're right about Iran being a dangerous state, but Iran never invaded other countries, used wmds, or tried to assassinate an American president. There were too many instances of possible Iraqi connections to everything from terror attacks using wmds to possible involvement with 9/11. While they might not all be true, there's too much smoke and too much evidence of Hussein's past crimes to assume they're all false. For instance the chemical mixer in the first 9/11 bombing was an Iraqi named Abdul Rahman Yasin. After the bombing he went back to Iraq where he was given shelter by Hussein.
The Irani's certainly support international terrorism, but not of the stuff that can be assumed or traced to Hussein can be traced to the Irani's. In my mind, Iraq was the more immediate threat.