It's hard to say, since the government—according to the US—has instituted a "near-total information blockade."

The Iranian government apparently learned its lessons from the Green Revolution protests and has slowed or shut down internet connections after announcing a national email service to compete with (and perhaps eventually replace) Google, Yahoo, and Hotmail.

The reports that have come out suggest the anti-government protests were relatively small and swiftly thwarted. From the BBC:

Opposition leader Mehdi Karroubi had been intending to attend the Saddeqiya street rally, but he was beaten up by members of the Basij as he emerged from his car. His son was arrested as he tried to intervene.

The reformist former President Mohammad Khatami was also reportedly attacked.

His brother, Mohammed Reza Khatami, and his wife, Zahra Eshraghi, the granddaughter of the late Supreme Leader Ayatollah Ruhollah Khomeini, were arrested but later released.

Other opposition sources said security forces had fired shots and tear gas at supporters of Mir Hossein Moussavi, Mr Ahmadinejad's main rival in last June's elections.

Later unconfirmed reports said Mr Moussavi was prevented from joining a rally, and his wife Zahra Rahnavard - also a key opposition figure - was "beaten".

And from the New York Times:

There were demonstrations and clashes between security forces and protesters across Iran, and state broadcasters seemingly cut away from President Mahmoud Ahmadinejad’s speech early, apparently as chants of “death to the dictator” arose in the crowd. But the opposition failed to reach a critical mass on the street, and the sentiment among the protesters was that the government had won the battle this day.