The prize goes to Martti Ahtisaari.
"Through his untiring efforts and good results, he has shown what role mediation of various kinds can play in the resolution of international conflicts. The committee cited Ahtisaari's 'significant' part in establishing Namibia's independence and his 'central' role in solving the question of the Indonesian province of Aceh in 2005."
Read more at CNN. The New York Times notes that Ahtisaari "has been associated over decades with peace efforts and quiet, cautious diplomacy from Asia to Africa and Europe."