Tim Buckwalter's notation is a one-to-one transliteration of the Arabic script for Modern Standard Arabic, using lower ASCII characters to encode the graphemes of the original script. This system has been very popular in Natural Language Processing, however, there are limits to its applicability due to numerous non-alphabetic codes involved.

Encode::Arabic::Buckwalter in Perl: http://search.cpan.org/dist/Encode-Arabic/lib/Encode/Arabic/Buckwalter.pm