"Computer terrorist" Kevin Mitnick is one of the world's most famous computer hackers and became a cause celebre after breaking into networks and stealing software at companies including Sun Microsystems and Motorola. Now <A HREF="http://www.cnn.com/2006/TECH/internet/03/08/tech.hacking.reut/index.html">Mitnick travels the world teaching</A> companies how to guard against people just like him. He argues that while sophisticated technology can help keep networks clean from viruses, it is useless if hackers can con a company's employees into handing over passwords by posing, for example, as colleagues.