This seems like a great idea! I think the kids would get a kick out of it if they saw and heard an author speak to them in their classroom. For one of my last assignments I listened to a webinar where they talked about a program on Scholastic that had authors Skype into the classroom. I will try to find what the program was called.
What a great opportunity and a way to make students more excited about what they're reading! In my math classroom, this specific Skype application wouldn't be too applicable, but there could be opportunities to Skype with engineers or other professionals who use math in their careers. It's a great way to be able to have a "guest speaker" in a way that's much more economical and convenient than the traditional method of having people actually visit and talk to the class in person.