The Internet is unquestionably the most extensive and accessible resource for information and commerce in history. But it is also providing a medium for new forms of crime, espionage, and even terror, targeting organizations and individuals alike. Broad awareness of vulnerabilities and defenses is needed to protect against all types of cyber attacks. While online learning environments provide a great opportunity to train large numbers of people, they have yet to demonstrate effectiveness in high-stakes situations. In an effort to better prepare cyberspace defenders, we are developing a multidisciplinary training program that encompasses topics from computer science, management information systems, and legal and ethical studies, using state-of-the-art online learning methods and technology.