Christ fits very well into eternal progression,he is the second member of the Godhead. He was and is a God from Everlasting to Everlasting. In LDS theology Christ is seen as the God of the Old Testament, he is the Creator of the Universe and everything in it, in the name of the Father and through the Holy Priesthood.  
 
So Christ has no need to progress any more, his birth and life was his completion of his progression. HE is a God of a world the God of our World, he reigns with the Father and the Holy Ghost.

Thanks for answering, I just realized you did. You bring up new questions for me. When you say "a god from everlasting to everlasting," are you saying Jesus as God had no beginning? I thought I understood that the god of this planet was previously a man on another planet, according to Joseph Smith (King Follet discourse). If Jesus is the creator of this world, who is Heavenly Father, and why are all prayers addressed to him? Thank you!