According to the Variety website, the score to The Dark Knight has been disqualified from competition in next year's Academy Awards.
Co-composers Hans Zimmer and James Newton Howard were sent letters last week from the Academy's executive committee explaining that the score does not meet their qualification standards due to their being three additional composers not listed on the official Dark Knight music cue sheet (composers Mel Wesson & Lorne Balfe and music editor Alex Gibson supplied additional material), and the rules state that at least 70% of the score must be attributed to the primary composers.
This technicality – which also disqualified the same team's score for Batman Begins in 2005 – is the source of much debate in Hollywood, since collaboration between composers and musicians with different styles is becoming more and more common in movie scores lately... but so far Zimmer and Howard have not gone on record as having challenged the decision.