I think the fact that you're not moving far, and you're doing it between school years makes it much easier. He'll still have his current friends, and he'll get to meet some more kids, too.
If he's nervous, remind him that there's no guarantee he'd be in a class with kids he's already friends with even if he was the same school, and that everyone feels new at the beginning of the year, so he'll be starting out even with lots of other kids.
And I agree with everyone who said make a big deal of setting up his new room! We moved 4 times when I was in school (same town) and I always loved the adventure of doing my new room.
If the new house has anything he's always wanted - a pool, walking distance to a playground, whatever, hype that up, too!