Country code: +261
Really comprehensive Yellow Pages and White Pages site for Madagascar. In French and English. When searching for people you need to put in the city as well - it does autocomplete the name if you type in letters in the search box but you don't get any results unless the place is included. Also offers reverse search (by telephone number).
This site is currently offline (as of Jan 2015) - if it's not back online within a reasonable amount of time, this link will be removed.
Yellow Pages business directory, with around 2,500 listings of businesses in Madagascar.