The Board of Governors of the Academy of Motion Picture Artsand Sciences approved rules for the 85th Academy Awards. The most significant changes affect the Music, Foreign Language Film, Makeup and Visual Effects categories.
In the Music (Original Song) category, the Executive Committee may recommend that a fourth songwriter for an individual song be considered in rare and extraordinary circumstances. This amends the rule that has been in effect since 2005, whereby up to two songwriters could be eligible per song, although a third songwriter could be added if he or she were found to be an essentially equal contributor.
http://deadline.com/2012/06/oscar-new-rules-affect-music-foreign-language-makeup-visual-effects-293910/