Islam by Country
Information on Muslim populations in the world from Wikipedia.
URL: http://en.wikipedia.org/wiki/Islam_by_country

Languages of Muslim countries
Information about Muslim countries and languages from Wikipedia.
URL: http://en.wikipedia.org/wiki/Languages_of_Muslim_countries

The Muslim World
Information and statistics about the Muslim population of the world.
URL: http://islam.about.com/library/weekly/aa120298.htm