The Dungeon Master's Guide has a small paragraph called "Divine Evil". It says that the cleric and paladin powers described in the PHB are designed with good and lawful good deities in mind. For evil clerics and paladins, the fluff should be changed without changing mechanics. The examples given are to exchange radiant damage (= holy light) with necrotic damage, ongoing holy fire with acidic slime, and being blinded by light with being blinded by clinging darkness.