The contract should expire at midnight, at least that's how it is with AT&T. You can switch to AT&T the day after your contract expires without being subject to an early termination fee. I assume you will want to keep your same phone number, so to do this you would simply go into an AT&T store or call customer service and tell them you want to "port" your number over from Verizon. All you will need is your Verizon account number and any passwords associated with your account. The port request will cancel your Verizon account and transfer your number to AT&T, so you will not need to contact Verizon directly to cancel your service. For about 4 hrs. after you port your number, you may still receive calls on your Verizon phone and you'll be able to make calls from your AT&T phone until the port request goes through.
