What was Origen's view of Jesus' soul? Origen believed in the pre-existence of souls (prior to conception), and that people's souls did things before their embodiment. For example, he taught that Jacob was loved and Esau hated because of what they did prior to their conception.

But what did he believe about Jesus' soul? Did it exist eternally? Or was it created in a moment of time like all other souls, so that at the Annunciation the incarnation had already begun?
Great question. It's a little of both. (We'd have to define what time means for God.) But I suppose we could infer Origen believed Christ's soul - as he believed of all souls - is eternal.

According to his writings, all souls were created by God at some time prior to conception.


  Let us inquire whether God, the creator and founder of all things,
  created certain of them holy and happy, so that they could admit no
  element at all of an opposite kind, and certain others so that they
  were made capable both of virtue and vice; or whether we are to
  suppose that He created some so as to be altogether incapable of
  virtue, and others again altogether incapable of wickedness, but with
  the power of abiding only in a state of happiness, and others again
  such as to be capable of either condition. (De Principiis)


And that Christ has one.


  Therefore, when the Son of God wished to appear to men and live among
  men for the salvation of the human race, He took not only a human
  body, as some suppose, but also a soul, and one like our souls in its
  nature, but like Himself in purpose and power, and such as could
  fulfill without turning all the wishes and dispensations of the Word
  and Wisdom. (De Principiis, emphasis mine.)


And all souls are eternal.


  The soul, having a substance and life of its own, shall after its
  departure from the world, be rewarded according to its deserts, being
  destined to obtain either an inheritance of eternal life and
  blessedness, if its actions shall have procured this for it, or to be
  delivered up to eternal fire and punishments, if the guilt of its
  crimes shall have brought it down to this.  ( Ante-Nicene Fathers re: Origen, Vol. 4, 1995, p. 240)