The first pillar is the statement of Faith (The Shahada) At least once in their lives they have to say, " There is no god but God, and Muhammad is his prophet."
The second pillar is daily prayer (Salat). Muslims have to pray five times a day, and at each time a call goes out to a mosque, inviting them to come pray. They can pray anywhere, but it has to be towards Mecca.
The third pillar of islam is Zakat. Zakat is a yearly donation to charity. It's used to help the poor, build mosques, and pay debts.
The fourth pillar of islam is Saum, (fasting). Muslims fast every day during the month of Ramadan. They do this to show that God is more important than ones body.
The fifth pillar is Hajj, (pilgrimage to Mecca). All muslims have to travel to Mecca at least once in their lives if they can. Pilgrimage focuses on visiting the Kaaba and walking around it seven times.