A prayer is the way we communicate with GOD. It is the conversation that one has directly with GOD. All you have to do to start this conversation is to say "GOD" and began talking. Talking to GOD and allowing him into your life lets him play a active role in it. Since GOD respects the free will that he has give everyone, you will have to pray to him to give him permission to act. One of the best places to pray online is GODPleaseHearMe. It allows you to access this power in a group environment since people who pray on here have a higher chance of getting their prayers answers because prayers are stronger together. This article call "Does God Really Hear You" is pretty good one that explains it all. Please check both out
http://www.squidoo.com/does-praying-online-work
http://www.godpleasehearme.com