2006 summer strike: Iberia
Airlines don't waste their opportunities to go one by one on strike each summer: one year, KLM's crew decided to stop their work, and some other years people working for Alitalia and Air France did the same. This time it is Iberia, the main airline in Spain, the one who decided not to work until its labor union and managers get some agreements.
This kind of measures obviously have some uncomfortable consequences: as many as 200 flights have been cancelled per day since last monday, and it's estimated that some 200.000 passengers will be affected by this strike.
The origin of this conflict is the creation of a low-cost affiliate airline named Catair, which was founded with the intention of eliminating some non profitable flights departing normally from the city of Barcelona. This will probably mean that workers will be fired.
But for now, if you had a flight booked with Iberia, I really suggest you to search for other options, because there isn't any estimated date to solve the problem.