Internal Contradictions of Prayer

Not only are statements about the efficacy of prayer utterly untestable, as Ed Brayton points out, but there's also a big problem with the whole concept of prayer itself. How, exactly, does prayer work? Are you pleading with God, seeking to influence its decision? This seems to be the viewpoint that Mayor David Miller of Lubbock, TX holds, as reflected in his request that the people of Lubbock pray for rain:

Nobody is going to tell God what to do and what not to do, but we are in a serious drought in West Texas, and since He is the man who controls the rain clouds, we're asking Him for His mercy and His help.

Surely an omniscient being already knows that the people of Lubbock need help. Mayor Miller makes is sound like God needs a little extra reminder or something along those lines, like it hasn't quite made up its mind what to do about Lubbock yet. But the notion that God can be persuaded implies that God can come to a less-than-perfect decision to begin with, which contradicts the idea of the omniscience of God. Is Mayor Miller seeking to demonstrate the piety of the people of Lubbock to God? If God is omniscient then it already knows their hearts; external demonstrations are unnecessary. Does God require people to pray because it likes the attention? The problem with prayer is that its based on an anthropomorphic understanding of divinity that was prevalent way back in the day when the stories and practices which would eventually comprise The Bible were being developed. In the Fertile Crescent and thereabouts this was an era of city-states, each with their own capricious, jealous, all-too-human patron divinity. Prayer was conceptualized as a way to cajole, wheedle, and otherwise persuade these deities to do the bidding of the folken. I'm certainly not the first person to point this out; there's good treatments of the subject in The Golden Bough and A History of God.