Who are the Muslims?
Muslims are those 1.9 billion people (per CIA World's Facts Book in year 2000), from all races, colors, nationalities and cultures who believe in One God (Allah) and accept Muhammad, peace be upon him, as the last Prophet. The majority of Muslims live in Indonesia, Bangladesh, Pakistan, Afghanistan, Iran, Turkey, Iraq, Syria, Jordan, Palestine, Egypt, Libya, Algeria, Morocco, Bosnia and other parts of the continents of Asia and Africa. Significant minorities are in India, China, Russia, Europe, North America (over 9.993 million in the USA) and South America.
A Muslim is a person who freely and willingly accepts the supreme power of God and strives to organize his or her life in accordance with His commandments. Hence a Muslim is any person anywhere in the world whose obedience, allegiance, and loyalty are to the One and Only God (Allah), the Creator of the Universe, and as such submits to the Divine Laws following the Sunnah (traditions) of the Prophet Muhammad, peace be upon him.

My Lord! Let me die as a Muslim and count me among the righteous

What are the Pillars of Imaan (Faith)?
Muslims believe in:
One and only God (Allah) with all His unique attributes;
Angels created by Him;
All the Holy Books originally revealed to the different Prophets, including the Torah, Psalms, Gospel (Bible) and the Qur'an;
All the Prophets through whom God sent His Message to mankind including Noah, Abraham, Ishmael, Isaac, Jaccob, Joseph, Moses, David, Jesus and Muhammad, peace be upon them all;
The Day of Judgment (the Day of Resurrection - Life after Death) and individual's acountability (reward and punishment) for good and bad deeds / actions; and
Al-Qadar (God's Pre-estimation), which means God knows everything. He knows what has happened and what will happen.
Why Muslims use the word 'Allah' instead of 'God'?
The word 'Allah' is the combination of two Arabic words ' AL Ilah' which means 'The God'; it is the proper name of the only Supereme Being Who exists necessarily by Himself. This word comprises all the attributes of perfection. This word is neither feminine nor plural and has never been applied to any other being. This word has no corresponding word in English or in any other language of the world. Allah in the One and Only True God's personal name. Nothing or no one else can be called Allah. That is why Muslims use the word Allah, His personal name, and not God.
It is interesting to note that Allah is also used for God in Aramaic, the language of Jesus, peace be upon him, and that all Arab Jews and Christians also use the word Allah for God.
How can someone become a Muslim?
Anyone who believes in One God and does not consider any other deity worthy of worship besides Him, all he or she has to do is to affirm the belief in the last Prophet of God Muhammad, peace be upon him through saying:
La Ilaha Illallahu Muhammad-ur-Rasoollallah

'There is no deity (god) except Allah (the One and Only True God) and Muhammad is the Messenger of Allah,'
and then follow the Qur'an and traditions of the Prophet Muhammad, peace be upon him. This is called the Shahadah (bearing witness to the Truth).