Aqeedah is belief, and for one to be a Muslim it is essential to have the correct beliefs as told by Allah and His Messenger sallallaahu 'alayhi wasallam. Many a time a person can leave the fold of Islam by certain actions or beliefs or become involved in Bid'at practices.
In today’s climate of diverse personal opinions and the emergence of various fitnah, it is imperative to have knowledge of the basic tenets of the Aqeedah of the Ahlus Sunnah wal Jamaa’ah.
IslamicTeachings.org have compiled articles and Q/A written by Scholars of the Ahlus Sunnah wal Jamaa'ah..... http://www.islamicteachings.org/forum/category/177-aqeedah-beliefs/