Prayer - What's the point??

I read a fascinating essay last night about prayer, called "Does prayer change God?", written by Philip Yancey. I've actually never read any of his books, though many of them have been recommened by various people that I respect (one of these days I'll get around to reading his book on Jesus). Anyway, as I was reading the essay last night, in which he talks about the Changelessness of God vs. the eternity/timelessness of God, he said the following:

Prayer brings together Creator and creature, eternity and time, in all the fathomless mystery implied by that convergence.

I find that an incredibly beautiful, humbling and terrifying thought. I can talk to God. God exists. Unbounded by time or space. Yet somehow, through some mystery, through Jesus Christ, and the work of the Holy Spirit, I can talk with God. And not only can I talk with God, but it has effect. Have you ever stopped to actually think about how incredibly cool that is?