The Internet and the WWW are critical to terrorist/global guerrilla communications. On the 8th of August, I will talk with Dr. Mark Last of Ben-Gurion University of the Negev in Israel. He and his team are working on a project to apply advanced data mining techniques to unearth terrorist activity on the Internet.
Dr. Last co-authored a paper, "Using Data Mining Techniques for Detecting Terror-Related Activities on the Web" (PDF) that provides detail on the approach. This proposed system works in conjunction with an ISP (with or without their permission) to determine potential terrorist activity. If applied to ISPs (and potentially Internet Cafes) across the Middle East, it might provide a means of detecting patterns of behavior that may be used to prevent attacks.
Here is Dr. Last's biography and a list of papers he has published.
UPDATE: Here's the audio of the interview. I hope you enjoy it.