Switch iPhone 4s to iPhone 5?

I just got an iPhone 4s on Sept 8 from Best Buy but now that the iPhone 5 was announced and I've seen it, I've decided I wanted it. What's the exchange/refund policy for Best Buy? And will Best Buy be selling the iPhone 5 for pre-order? If anyone knows.
My service is Verizon if that matters

The exchange policy is usually about 15 - 30 days