Time has a pretty good article on the insurgents here. The thing I don't buy is that they all went from being Saddam loyalists to all being radical jihadists loyal to Zarqawi. I'm sure that once Saddam was captured, the insurgents loyal to him could have become more fundamentalist. But there have been all types of insurgents from the very beginning, especially nationalist ones, as evidenced by Sadr's recent uprising. I don't see why insurgents have to be portrayed as religious radicals or Saddam "dead enders", when, quite obviously, they are all fighting for one thing. The expulsion of US troops and control of their future. I guess it makes it easier to hate them if they're all extremists and psychos.