There's an entire RAND book about it, and that's probably the best source.
http://www.rand.org/publications/MR/MR1382/
Pay special attention to Chapters 1 and 10.
Netwar is especially interesting if you know a bit about computers and networks. The basic idea is that the networked structure exists on the organizational, doctrinal and tactical levels in the most successful modern terrorist organizations. al-Qaeda, for example, is both a "hub and spoke" arrangement, with the cells communicating directly with one central command and a "wheel" arrangement, wherein they can communicate with any other cell in the network directly. Interesting stuff.