The Proper Pronunciation of the Arabic Letter ض (Zhoaid/Dhoaid)

It is important to know that there are two major dialects in which the Holy Quran is read. These dialects are

• Hijazi
• Panipatti

Hijazi is the dialect which is used mainly in the Middle East (e.g. Saudi Arabia) and Panipatti is mainly used in the Indian subcontinent (i.e. Pakistan, India).
According to the Hijazi dialect, the letter "ض" should be pronounced in such a way that the sound is a bit similar to "dh". However, the panipatti dialect says that this letter should be prononounced in a way that the sound is similar to "zh".
I recommend the Hijazi dialect because it is followed by the Arabs and the Prophet Muhammad (PBUH) was an Arab.

Rules of Recitation

Salam!
Here's a webpage which clearly tells the rules of recitation.
http://quran.al-islam.com/Ahkam/Tree.asp?ID=1&t=TreeSub&l=eng&RecNo=2&Parnt=1
Please visit it.
Wasalam!