I found an AT&T Iphone4 and want to use it.?

I found an ATT Iphone 4 and its been remotely wiped. I currently have service with Verizon, but want to know if I will have trouble going to an ATT store and starting an account with them. Please keep the self-rightousness to yourself. All the phone info is gone and I am not going to work hard to get back someone else's lost phone.