As a matter of fact, "Mozzafar" is incorrect; it must be "Mozaffar"; tashdid is on "f" and not on "z". Further, "ad-Din" is better than "od-Din" and both are better than "al-Din". In point of fact, even in Arabic "al-Din" is not pronounced "al-Din"; the letter "D" in "Din" is a so-called Shamsi letter (to be contrasted with so-called Ghamari letters) whereby the "al" in "al-Din" renders the "D" in "Din" a moshadad "D" (i.e. a "D" with a tashdid), at the expense of "l" itself not being pronounced (in this connection, note the two "d"s in "ad-Din", one in "ad" and the other in "Din"). For details concerning Shamsi and Ghamari letters, consult this page. To summarise, the correct transliteration is Mozaffar ad-Din Shah. I must add that in Persian vernacular, one often pronounces the name as Mozaffar ed-Din Shah (note the "e").