The real plan is more subtle and the real goal is more insidious.
The ultimate goal is to make Islam the dominant religion in the world, and make sharia law the primary legal system.
The plan is to destabilize economies or just let them fall apart on their own (such as in many African countries today) and then move in with massive quantities of money to build infrastructure, revitalize the economy, etc. all in the name of Islam. The Islamic benefactors will then be viewed as benefactors and will gain influential positions in government, eventually in positions where they can enact their legal "reforms" to bring the country's laws closer and closer to sharia law and bring society closer to their ideal as defined by Islam. It will be a slow process so as not to cause alarm, though in smaller and less influential countries the changes may be done more rapidly because, I hate to say, the majority of the world simply won't care what happens to some really, really poor African country that is not even a tiny blip on the economic or political radar.
Read the quote that Schneier had about one Al Quaeda "dollar" spent "defeating" millions of US dollars. The point is to cause economic instability and then have Islamic "benefactors" come in and save the day, at the cost of altering our culture to meet their requirements.
I'll leave it as an exercise for the reader to explore the potential implications that this could have on US, Mexican, and Canadian societies. (Canada and Mexico will eventually be targets, my friends - they're just going after us first because we have more economic and political power, but I doubt they'll be satisfied until they control everything, and Canada and Mexico both have so much to offer that they should be fairly high on the list of next targets.)