The Iranian revolution was not so much about Islam more than Islam enabled the revolution. When the old leader came back after the revolution in 1953 (which was staged by the CIA and the British) he cracked down on the population in such a manner that resentment built up.

However one place where the crackdown did not apply was mosques since attacking a mosque in a majority muslim nation is a sure fire way to start a revolution, so the religious leaders in these mosques would preach and slowly win over the people. It also gave these people a gathering place with which to plan and strategize.

So rather than saying that the revolution was about Islam its more accurate to say that the Revolution was enabled by Islam. Much like Vietnam and communism, the Iranian people embraced an Ideology in order to win themselves freedom. You can see this in the way that both nations are much more liberal than their predominant ideologies would portray, slowly moving back towards a more democratic and capitalistic state.