I'd like to expand on my answer.
Please do
not get your kid a puppy. This is about him learning that change happens in life and that a person can be okay with change. A puppy (or any other bribe) distracts from learning that lesson.
Talk about the move with him. Compare where you are living now and where you are going, talk about how life is going to be different but kind of the same.
What's he like about living where you are now? Find some things to talk about in the new place that are like them but different. (We've got some big trees here and where we are going they've got big trees and there's some little ones. They call them pine trees.)
Let him choose some changes. Where does he want his bed to be in his new room? By this wall or that wall? ("Oh, good choice, kiddo!") Shelf of toys over here or over there? You can do the whole thing in your minds. Let him imagine the changes and feel that the changes are going to be okay.
And friends? Tell him one of the reasons he has so many friends is that he is so good at making friends. And...... there's going to be friends there, just like where you are now. Compare new to the present and discribe the new as different but okay.
My two kiddos and I moved a bunch of times. Most of the time they were settled in to the different but new before their old man was.
Joe(ch-ch-ch-changes)Nation