Origin
The Sunni-Shiite split actually started right after Muhammad's death in 632. His death led to the dispute over his successor. Since he was the founder of Islam, he was the undisputed leader. However, Mohammad died without a son (who would have automatically inherited his father's authority) and without a clear will.
Value
The Muslims eventually split into two groups, the Sunnis ("tradition") and Shiites ("party of Ali"). Both sides had differing views on both who should be the leader of the Muslims and on the religion as a whole.
Purpose
Today's Sunni-Shiite conflict revolves around the Sunnis acting violently against the Shiite government. The tension has escalated over the years, which led to the direct escalation violence and seriousness of the situation.
Shiites belief of ruling
The Shiites believed that whoever had the spiritual authority to succeed Muhammad should rule.They supported Ali, Muhammad's cousin/son in law because he was the only blood relative of Muhammad. Ali eventually succeeded Abu Bakr, which is what led to today's Shiite run government in Iraq.
The Shiites believe in Ali accords him divine status.
The name Shiites actually means "party of Ali" since they were his followers when deciding who should succeed Muhammad.
The Shiite doctrine of the infallibility of the Imams position them as Prophets along side, or even above, the Prophet Mohammad.
The Shiites have two additional versus in their Quran.
They claim that the the versus added were originally passed down to the Prophet and proved his choice of Ali as his successor. They claim it was deleted from the actual text and the Shiites simply re-inserted them into its version of the Quran.
Sunnis belief of ruling
The Sunni's believed that whoever was best equipped politically to maintain the Muslim empire should be in charge.They supported Abu Bakr, Muhammad's father in law, who was eventually named the first caliph (The chief Muslim