I've never been satisfied with Clerics memorizing spells like a Wizard. Nor am I comfortable with the unbalanced level of versatility enjoyed by the Cleric class in 3rd edition. So, I've made a few changes...

1. Clerics do not have access to all of the spells for their level. Depending on the nature of their God, they will have access to a smaller subset of those spells. For those players who choose to play a Cleric I will put together a spell list particular to their God from which they will pick their spells.

2. Clerics do not "pray" for spells the night before they use them. In this campaign Clerics will use their spell slots in the same manner as a Sorcerer, calling on the power of their God at the moment it is needed. Being a faithful Cleric, and behaving in a manner appropriate to one's God, will mean those spells will flow from the Cleric freely. Being an unfaithful Cleric, and poorly representing the will of one's God, will mean the opposite.