"Um...A gift registry? I don't think we've ever been asked THAT before," he said. "We don't have one. We're kind of a specialized store, you know." Yes, we do know. And it's the kind of specialization that we like. But even Home Depot has a gift registry service, so what's the hold-up Apple? Don't you realize that geeks get married and have babies too?
Sadly, it looks like Megan must rely on word of mouth instead. Don't forget, Apple does have a limit on how many gift certificates you can redeem at any one time online. I think it's something like 4 cards for online purchases but unlimited for in-store ones. Check with an Apple representative for details.