The raising of hands is an ancient Christian act of worship which and, as Gregory pointed out, can be seen among certain Orthodox cultures. During the evening psalm of vespers (Psalm 140) , we chant about the "lifting up of my hands as an evening sacrifice." In most Orthodox Churches, you'll find an icon of theTheotokos with raised hands directly above the altar. The priest certainly raises his hands at various points during the liturgy, e.g. at "let us lift up our hearts..." during the Anaphora (the most ancient part of the liturgy) which ,by the way, is when the people are supposed to as well.
It seems to me that this act of praise and worship has been confined to private prayer and no longer practiced publicly among most Eastern Orthodox. Some may even be scandalized when they see it done in an Orthodox Church and may dismiss it to being "Protestant." That's unfortunate and should be remedied. We are to worship with our entire body during the Liturgy, e.g. making the cross, prostrations, raising of the hands, exchanging the kiss of peace and singing.
The fact is that the early Christians really preferred praying with "outstretched hands." The Holy Apostle Paul mentions it in 1 Tim. 2:8. The book Earthen Vessels by (now Orthodox) Fr. Gabriel Bunge covers the topic of methods of prayer really well.
