Wo!
A brilliant and rules-savvy answer*, and right on the first page, too! Go FAQ!
* - Q: When a cleric has a temporary bonus to his Charisma score, does it affect his turning check or turning damage? Does it change the number of times he can turn or rebuke per day?
A: [Summarizing] Yes. He gains extra uses per day. However, track uses expended, rather than uses remaining. So if he starts with 4, gains 2 (for a total of 6) through a temporary boost, and uses 5, he's used 5 of 4 available once the temporary boost runs out. If he can get a bigger temporary boost, he can gain more uses, but not until he gets at least 6.