Judith Miller has a long piece in City Journal on ETA and terrorism in Spain. Go read it. There are a few small inaccuracies, but there are also some things I didn't know, such as the following paragraph:

American intelligence and counterterrorism officials have repeatedly traveled to Madrid, American officials say, to urge the Spanish government to close loopholes that international terrorists have exploited in its legal system, reduce the self-defeating envy among Spain’s warring police forces, improve police training, and step up bilateral and multilateral counterterrorism cooperation. Some of this has occurred. Spain recently approved the stationing of an NYPD detective in Madrid to monitor counterterrorist operations. But most U.S. pleas have had limited impact, perhaps hampered by the tension between Washington and Madrid over Iraq and other issues.