I wouldn't recommend switching to AT&T, but, if you really want to do this, I would suggest you NOT terminate your service until you get your iphone and sign up with AT&T.(call verizon and give them a later date quick!) I would hope you are not paying the termination fee, and thus if you are not, you would be out of contract. If you are out of contract, then you can terminate your service when you want!(and get a bill up to that day, prorated) To ensure you get your number, you will have AT&T do a LNP (port-in) and you will be from 3-24hs with mixed service (using both phones... one to recieve, and one to make calls.) You will get billed by Verizon for what you had used up to the day of termination. Your voice mail with Verizon will not transfer over, and will be available until the transfer is complete. You will get a message on your Iphone when the port-in has completed aswell. On that day you will get billed by both services, but it is worth it for ensuring your telephone number and keeping service. If anything else, ask me.