I have quite a few flights scheduled over the next 10 days so am trying to watch the Grimsvotn ash cloud closely.
Eurocontrol, the European Organisation for the Safety of Air Navigation, is doing a pretty good job with updates via twitter. Check it out.
500 flights have been cancelled today, primarily in UK and northern Germany. To give that number some context, about 29,000 flights operate in Europe on an average day.
The Haunting by Robert Longo, originally uploaded by pirano.