Time has a pretty good piece online called "3 Lessons from London". It's worth your time.
EUROPE IS BURNING
The attacks on 7/7 were a reminder that Europe is, more than ever, a center of the threat. That's partly because European nations like Britain have a tradition of welcoming immigrants from North Africa and Pakistan. The children of those immigrants–many of them jobless and ghettoized in insular suburban tracts or city centers–often feel alienated from the ambient permissiveness of London or Paris. Alienated and bored: Peter Bergen, author of Holy War, Inc., wrote in the New York Times last week that the unemployment rate among 16- to 24-year-old Muslim men in Britain is 22%. He cited a British government report leaked to the Sunday Times in London last year that estimates between 10,000 and 15,000 British Muslims support al-Qaeda and similar groups.
THE ENEMY ADAPTS
Cells from England to Somalia manage their own ops. Consequently, says a European-based U.S. official, "their chances are low of taking over a plane again … But they can obviously get down into the subway system. If you make yourself a harder target, you push them to softer targets."
LOOK BEYOND IRAQ
But the most enduring lesson terrorism experts have learned is that a movement as far-flung as bin Ladenism can't easily be contained. "It's been a constant truth in this discipline that by the time you've figured out what Islamists are up to, they've already moved on to something else," the French official says.