There are different approaches to romanizing the Arabic script.  However, due to the nature of written and spoken Arabic, there are numerous problems when transliterating Arabic into English and other European languages.  Common problems include:

• transliterating Arabic phonemes that do not exist in English or other European languages
• how to represent the Arabic definitive article which is always written the same in Arabic but has different pronounciations depending on the context the
• representation of Arabic short vowels (usually i u or e o, which accounts for variations such as Muslim/Moslem or Mohammed/Muhammed/Mohamed).  

Click here for more information on the Romanization of Arabic and the specific methods and problems.

Transliteration guide from Arabic script to the Roman script taken from the Library of Congress.  

More information on Arabic to Roman script transliteration can be found at the Library of Congress website.