G.L.
As the wife of a career military man (now retired), I've had loads of practice with moving with kids. One advantage I do have that you don't is that for my kids, it's just a normal part of life. But it has always been harder for my son. I read the other responses, and I agree that a marketing campaign for the new location is a good place to start. Since your move is a year or two in the future, would it be possible to take a vacation trip to the state you'd be moving to? It would give him a chance to look around a little, and you a chance to play up the cultural/recreational advantages of the new location.
Since it sounds like a temporary move, I'd also emphasize to him that it's not forever. (If you can honestly say that - if there's a chance that the move is going to be permanent, don't go there.) Of course, at his age a few years seems like forever. Show him all the different ways to keep up with his friends - camera phone, social networking, blogging, etc. Promise him vacation trips back to Utah (and be prepared to honor that promise).
And the toughest part - your son is probably feeling powerless in the situation, which may be the root of his trying to insist that he will not move. And he IS powerless in this situation - it is his parents' choice, not his. So try to find a way to give him a few choices. Listen to his input about where to live, what schools look good to him, etc. Ask him to help with some of the decision-making for the move, such as what to take, what to sell, what to store, etc. If he chooses to sell some of his stuff, let him keep the money. Offer him the opportunity to get involved in new recreational and social activities in the new place. (This support could include the purchase of new athletic equipment, lessons, club membership, etc. - for example, I got my daughter to fell better about an impending move with the promise of riding lessons, since we were moving to a horsey place. Then her bother and I joined her in learning to ride, thus turning it into a family experience.) He is also old enough to understand that his happiness depends on HIS choice of attitude (even though he won't like hearing about it from his parents). Acknowledge that he feels frustrated or sad about the move, but also let him know that he controls whether these emotions rule his experience of the move.
Good luck.