See this documentary if you have the chance. It takes a look at the history of the American arms industry and wars of intervention over the past 60 years. Much more balanced and intelligent than Michael Moore or Loose Change. It's chilling the way Eisenhower predicted and warned against the growing military-industrial complex, and the way the film puts the current situation in the context of his speech is brilliant.
Here is a shorter, low quality version. I still suggest you see it in theatres if you can.
http://www.informationclearinghouse.info/article8494.htm
And if you're really lazy just watch the trailer:
http://www.apple.com/trailers/sony/whywefight/trailer/