God, Eternity, and Time

"God is eternal" is a standard belief of all theistic religions. But what does it mean? If, on the one hand, "eternal" means timeless, how can God hear the prayers of the faithful at some point of time? And how can a timeless God act in order to answer the prayers? If God knows what I will do tomorrow from all eternity, how can I be free to choose what to do? If, on the other hand, "eternal" means...