I had dinner with a good friend of mine last night. He is a devout Muslim and I asked him what the difference between a Sheit and a Suni were. He gave me some good insight that I have not gleened from others or the skimming versions of our media and general population.
Here is the boiled down version:
A Sheit believes that when Mohammad died that the Eman (sp), leader of Islam, should be a blood decendant. That left the nephew of Mohammad since Mohammad only had girls as direct descendants.
A Suni believed that it should be the most Holy and devout follower of Islam and did not have to be a blood relative.
Then there are the Buhkari (sp) that believe that there should be no division between Islam and that everyone should be a Muslim: not a Suni or Sheit. (Side note: Since they believe that there shouldn't be sects, the Sheit and Suni refer to them as a different sect...irony!)
Al Queda believes as the Buhkari do. That there should be no divisions between Islam. That's why 'they' have no issues with bombing Suni and Sheit's because, in their eyes, they also are not following Islam as they feel it should be followed.
Simplicity ahead: Haji, my friend, says that the Koran states that a Muslim should follow the correct path and not worry about others. So if you want to walk with him, great, if you want to go left or right or backwards, fine. Not his issue...it's your issue.
Back in the early times of Islam, there were warring clans. So when they decided/wer forced to convert to Islam, they chose the opposing faction as their "enemy". That's why if you look at a map of the middle east, you have 'layers' of Suni and Sheit. Basically, if I didn't like your village and you are a Suni, then I'm going to be a Sheit.
This is one reason why they fight each other. Combine that with the feudalistic version of Islam (My father was 'king' therfore I should be) that the Sheit's follow and the but you're not the most Holy that the Suni follow and it's a recipe for fighting.
I never knew what the difference was, so having this info really helped me get a bit of a clearer picture on things. Thought it might help others in the Knowledge department.