Interesting quote i found from one of my favourite blogs...
“Jesus has been emphasizing his Messianic claim. He does not say that before Abraham was born the logos existed; he says ‘I am.’ It is Jesus the Messiah, Jesus the man whom the Father had consecrated to the Messianic work who speaks. Just before this he had spoken of ‘my day,’ which Abraham saw (John 8:56), by which we must understand the historical appearance of Jesus as Messiah. Abraham had seen this, virtually seen it in God’s promise of a seed (Gen. 12:3; 15:4, 5) and had greeted from afar (Heb. 11:13). And now it is this one who consciously realizes the distant vision of Abraham who says, ‘Before Abraham was born, I am.’ Jesus, therefore, seems to affirm that his historic Messianic personality existed before Abraham was born. If that be the case, then its existence before Abraham must be thought of as ideal.”
The Endnote says, G.H. Gilbert, The Revelation of Jesus, A Study of the Primary Sources of Christianity, pp. 214, 215.