If you have some catching up to do on Islamic history--what I do not know about the middle east and/or Islam would fill several medium-sized countries in the region--you should go here and read or listen to the history of the Sunni-Shia conflict. NPR has a series that begins with an explanation of the split and takes you through how it has played out to the present day.
One of the unintended consequences of the Iraq and Afghan war is the rise of Shiite Islam, as embodied in the state of Iran and the sizeable minorities in Syria and Lebanon. Sunni Islam has ruled the Islamic world for much of the post-Mohammad era, but the Shiia are rising fast. Some people believe that the Sunni-Shiia conflict could erupt into a general sectarian war among all the above-mentioned states, admittedly not the happiest thought.
Once you get a handle on this split, you will be far ahead of many of our legislators in Congress. There's a guy who works for one of the Capitol Hill newspapers who regularly asks Congressmen and women what the split is about, and to which tradition Bin Laden and Al-Quaeda belong. Quite often, they are clueless. Do you know this off the top of your head? If not, slink off quietly to the website and autodidact, i.e. teach yourself. As Harry S. Truman said so memorably, there is nothing new in the world except the history you do not know.