I have to say, your post made me giggle a little. As just a year ago we faced the same thing, but in reverse. We spent ten years in Texas, and had to move to Georgia. For my kids (13,10, and 4 now), that was most of their little lives, so it was somewhat scary for them. But then, we were lucky as we got to spend so long in one place. We're a military family, so this is close to unheard of.
Staying positive and making it a great adventure for the kids is actually the best way to go about it. Start helping them research their new home. Show them pictures and videos of landmarks, and find fun places you'll be able to explore once you get there.
Before going, try to go to all the places you love the most at your current home. Take lots of pictures and video. have them make up a book (with pictures if possible) full of their friends addresses, phone numbers, and emails. That way they won't feel so much like their 'losing' their friends.
If you have the time during the move, if you're driving that is, stop here and there and have picnics. Take pictures, and show them where they are on a map. Maybe have them help make a scrap book. "Today we stopped for lunch in *place*." And have them write out what they saw, what they thought of the place, what everyone ate, etc.
Be extra sure to let them pack a few favorite things, stuffed animals, other toys, clothes, books, special pillow and blanket, etc. That way the new place won't seem so foreign and daunting. If they have their favorite comfort items with them, it helps prevent the scary because then, "Mr. Panda isn't alone in a box." As my daughter recently put it.
If you can, and know some, talk to military parents who've been through this a bazillion times.
Above all, do what you've been doing. Stay positive and upbeat, because as soon as mommy thinks it's scary, it becomes scary to them.
Going to link you to a pretty good article for military parents dealing with moves, I know it helped me the first few moves, and it was a good refresher with this most current one.
http://www.military.com/spouse/content/military-relocatio...
Feel free to PM me if you have any questions or just need to chat.
Remember, your not losing your home, your neighborhood just got a lot bigger. Good luck and grats to your husband on the new job!