There was a presidential election where the incumbent president (Mahmoud Ahmadinejad) was announced as the winner even though he was behind in most polls.
After the election results were announced, many people did not believe the results. It is believed by many people that the re-election of Mahmoud Ahmadinejad is a coup by the Iranian government to not allow the new government (as chosen by the people) to take power.
Iranians (especially the young and middle class people within the major cities) are now protesting the election results as the government tries to contain the protests. State media outlets are acting as if nothing has happened. Telephone and internet access is being cut-off or severly limited. Universities are being shut down by the police. Many opposition leaders are being arrested.
The world is waiting to see what will happen. Can the opposition protestors use the internet and messaging systems to continue their protests or will the Iranian government forces prevail and restore their power?
It seems clear that even if the government restores order in the short term, the long-term legitimacy of President Mahmoud Ahmadinejad and the Supreme Council has been weakened considerably.
It seems Iran is split similar to how the United States is split. There is a rural, religious, conservative faction that supports the current President. The opposition protests are largely made up of an urban, middle class, secular faction. Your basic Republican Democrat split, but on a different level and within a different environment.
Hopefully, the urban, middle class, secular faction will continue to use the internet to break down the media monopoly held by the religious leaders. Open information and communication is crucial to the future success of the "Democrat" faction.