There was an uproar in Sudan last month when controversial cleric, Hassan al-Turabi, issued a fatwa in which, among other items, he declared that it was permissable for a Muslim woman to marry a Christian or Jewish man.
Turabi's decree led to the first such marriage of its kind in modern Sudan. A Muslim woman married a Christian man in a church in Al Qadarif on Sudan's eastern border, adjoining Ethiopia.

Still that's the exception to the rule.