Can a Paladin have more than one Smite Evil working at the same time, against different foes?
Once per day, a paladin can call out to the powers of good to aid her in her struggle against evil. As a swift action, the paladin chooses one target within sight to smite. If this target is evil, the paladin adds her Cha bonus (if any) to her attack rolls and adds her paladin level to all damage rolls made against the target of her smite...
The smite evil effect remains until the target of the smite is dead or the next time the paladin rests and regains her uses of this ability. At 4th level, and at every three levels thereafter, the paladin may smite evil one additional time per day...