What is the difference between the Sunnis and the Shiites?

We often hear of them in the news associated with the Muslim people. However not too many people actually know who the Sunnis and the Shiites are, or what the difference between them is, or why they do not agree with each other. It all started when the ruler of the Islamic religion Muhammad died in 632 A.D. Muhammad had never chosen or instructed who his successor would be. It was decided that the first four caliphs or leaders, would be leaders for life and be family of Muhammad. The Caliphs were chosen to protect and spread the Islamic religion. The first was Muhammad's father-in-law who was Abu Bakr and the last was Abu's son-in-law Ali. Ali's rival was the governor of Syria named Mu' awiyah. Ali was unfortunately killed by a fanatic follower. This gave Mu' awiyah the chance to seize power and so he became the first caliph of the Umayyad Dynasty. However, Ali's son Husayn refused to allow the Umayyad Dynasty to seize control of the throne. In return Husayn and his followers were killed by Umayyad troops. This sparked a division in Islam. Those who agreed and felt it was okay for the Umayyad Dynasty to take over were the Sunnis and were the majority of the Muslim community. Those who did not agree belonged to a smaller Muslim community called the Shiites. This feud still lives on today and is sometimes reported in news often ending in violence.