During the night, just before 03:00 local time, there was an increase in seismic activity near the town of Grindavík. Soon after an immediate evacuation was ordered. At 07:57 a volcanic eruption began near the town.
The inhabitants had been allowed to return after the end of the previous eruption but many had yet to do so. There had already been signs of activity and the town was supposed to be evacuated by Monday.
As I write this, the lava-flow is about 450m (about a third of mile) from the edge of town.
The best way to keep of with news of the eruption is at the RÚV (Icelandic state radio and TV) website. They also have webcams near to the eruption site.