Videos of the protests in Iran are trickling out despite reports of cellphone and text-messaging services being down, another sign that organizers are finding ways to evade tight government controls to get the message out.

According to tweet messages and opposition websites, protesters gathered at different meeting points in Tehran to head toward centrally-located Imam Hossein Square and Azadi Square, following a plan previously announced by opposition leaders Mir Hussein Mousavi and Mehdi Karroubi. Despite the government...