I recently had the privilege of listening to two excellent discussions. The first was on the concept of pre-existence in the writings of second temple period Hebrews, and the second was on the nature of pre-existence in the gospel of John (particularly in regards to the person of Christ). Rather than explain it all here, I'll let Dr. Dustin Smith (dustinmartyr.wordpress.com) tell you all about it.
Here is part 1: Pre-Existence in Ancient Jewish Thought
Here is part 2: The Pre-Existence of Jesus in the Gospel of John
Blog by Matthew Janzen. Lover of Yahweh, Yeshua, my wife and 5 children. All else is commentary.