How to become a Muslim
If anyone has a real desire to be a Muslim and has full conviction and strong belief that Islam is the true religion ordained by Allah for all human-beings, then, one should pronounce the "Shahada", the testimony of faith, without further delay. The Holy Qur'an is explicit on this regard as Allah states:
"The Religion in the sight of Allah is Islam." (Qur'an 3:19)
In another verse of the Holy Qur'an, Allah states:
"If anyone desires a religion other than Islam (Submission to Allah), Never will it be accepted of him; and in the Hereafter he will be in the ranks of those who have lost."(Qur'an 3:85)
If a person does not pronounce the Shahada and enter Islaam, we cannot say that he is a Muslim, even if he admired Islaam and recognized that it the best religion, a great religion, and so on. Abu Taalib, the uncle of the Prophet (peace and blessings of Allaah be upon him) died a kaafir (non-Muslim), and Allaah forbade His Prophet to pray for forgiveness for him, even though he used to defend the Prophet (peace and blessings of Allaah be upon him) and said in his poems: "I do know that the religion of Muhammad is better than all other religions of mankind; were it not for fear of blame or slander, you would find me accepting it completely."