There's a good long read by John Arquilla in Foreign Policy magazine this month. He argues that a concept of cyberwar he proposed some 20 years ago with David Ronfeldt "has become a reality," in that battlefield information systems have "profound impact" as a disruptive force "in wars large and small." But Arquilla goes on to argue that a parallel notion of cyberwar popularized by others– "less a way to achieve a winning advantage in battle than a means of covertly attacking the enemy's homeland infrastructure without first having to defeat its land, sea, and air forces in conventional military engagements" — is a bunch of hype-y hooey.
