Crazy stuff. Seemingly a small eruption, between 150 and 400 meters below fairly thin ice. Magma reached the surface about an hour ago. More info here & here.
Alternatively watch this site for updates.
“Not to be an alarmist, but some have been comparing the conditions leading up to the eruption to the 1783-84 eruption of Laki that changed the climate so much that the Mississippi river was frozen in New Orleans and ice floats were spotted in the Gulf of Mexico. As "cool" as that might be, an estimated 6 million people died from complications of the eruption (mostly widespread droughts). Let's hope that's not really the case this time.“
http://www.livefromiceland.is/webcams/bardarbunga -- Live stream for anyone who'd like to watch the development of the eruption.