Spell Casting (Divine):
Orisons: Clerics can prepare a number of orisons, or 0-level spells. These spells are cast as any other spell, but aren't expended when cast and can be used again.
Spontaneous Casting (Inflict): A good cleric (or a neutral warpriest of a good deity) can channel stored spell energy into healing spells that he did not prepare ahead of time. The warpriest can expend any prepared spell that isn't an orison to cast any cure spell of the same spell level or lower. A cure spell is any spell with "cure" in its name.
Chaotic, Evil, Good, and Lawful Spells: A cleric cannot cast spells of an alignment opposed to his own or his deity's. Spells associated with particular alignments are indicated by the chaotic, evil, good, and lawful descriptors in their spell descriptions.
Aura (Chaotic, Good): A cleric of a chaotic, evil, good, or lawful deity has a particularly powerful aura (as a cleric) corresponding to the deity's alignment (see detect evil).