I hope we find out rather soon whether the Madrid bombings were the work of al-qaeda (and part of the International Jihad Movement), ETA (the Basque separatists in Spain), or some combination thereof. Listening to the Spanish official (or reporter?) on Talk of the Nation today, my gut was thinking this was not ETA, in that the organization roundly condemned the attacks- something they never, apparently, do when it is their work.
Of course, in any event this mornings tragedy was horrific. I read about the candle-light vigil in Barcelona- anything to vigil-ize it in the states? not sure.
Calpundit points to this, which is enough to lean me away from thinking this was solely ETA, if them at all. Why is that important? For starters, SPain has already convinced the UN Security Council to condemn ETA. Such condemnations are ill-used when we don't have solid info on the terrorists. Further, the implications of who did this might be, as Kevin Drum notes, interesting. Drum writes:

In any case, if it does turn out to be al-Qaeda, I wonder how that will change things? It's been something of an article of faith in America that if 9/11 had happened in Europe there wouldn't have been so much resistance there to the Iraq war. These train bombings aren't 9/11, of course, but they're plenty bad. Will it affect European opinion much about America's approach to fighting terrorism?

Finally- perhaps more on this later- I'm finding something off about the continued reporting of the, to paraphrase, van containing detonators and an audio tape with passages of the Koran.
The detonators, it seems, would do the trick for the story on identifying some suspicion. Why is the tape included? it was apparently one available at any store. I do hope we're not heading to a social context wherein we identify terrorist by way of refering to audio tapes of the Koran.