You've probably heard by now that an Egyptian Al-Qaeda franchise is claiming responsibility for the attack. It's worth noting that Al-Qaeda got its start in Egypt.
Mark Erikson of The Asia Times wrote an excellent four-part series about the origins of global jihadist terror, "Islamism, Fascism, and Terrorism." It's quite a story, involving Nazis, the British and even the CIA. Highly recommended.
John Loftus, the Justice Department prosecutor who uncovered many of the connections in CIA files, gave an overview in a speech last summer that's made the rounds on the Internets. Warning: may contain exaggeration.