Dear Kate,
Moving away is hard, and leaving your close friends behind is really tough. Talk to your friend about how you can stay connected even when you live far away from each other. Take advantage of emails, IMs, phone calls, and letters. And figure out how the two of you might be able to get together in person once in a while. While you're trying to keep your old friendship strong, try to be open to developing new friendships in your new neighborhood.