What is Islam?

The name of the religion is Islam, which comes from an Arabic root word meaning "peace" and "submission." Islam teaches that one can only find peace in one's life by submitting to Almighty God (Allah) in heart, soul and deed. The same Arabic root word gives us "Salaam alaykum," ("Peace be with you"), the universal Muslim greeting.

Who is a Muslim?
A person who believes in and consciously follows Islam is called a Muslim, also from the same root word. So, the religion is called "Islam," and a person who believes in and follows it is a "Muslim."

How Many and Where?
Islam is a major world religion, with over 1 billion followers worldwide (1/5 of the world population). It is considered one of the Abrahamic, monotheistic faiths, along with Judaism and Christianity. Although usually associated with the Arabs of the Middle East, less than 10% of Muslims are in fact Arab. Muslims are found all over the world, of every nation, color and race.

Who is Allah?
Allah is the proper name for Almighty God, and is often translated merely as "God." Allah has other names that are used to describe His characteristics: the Creator, the Sustainer, the Merciful, the Compassionate, etc.
Muslims believe that since Allah alone is the Creator, it is He alone that deserves our devout love and worship. Islam holds to a strict monotheism. Any worship and prayers directed at saints, prophets, other human beings or nature is considered idolatry.

Source:http://islam.about.com/