Maybe this will help someone... In a rush, I skipped over the step during initial set-up that asks you to call Verizon, assuming I could still activate it later. Big mistake... I tried a 1000 different things, including erasing my phone and starting over a half dozen times, and I also went to the website to activate it, but nothing worked!
So I finally called customer service. First it'll ask you to press '1' if you're calling to activate your phone. Then it will ask for your PIN twice... If you don't know it, just hold and it'll put you thru to a live person. I told the guy I never got a PIN and gave him my last 4 SSN instead. They will then ask you for your IMEI and ICCID numbers. You find both under Settings> General> About. After that, they'll ask you to make a test call on your new iPhone (which won't go thru if you're calling on you old iPhone [since you're actively using that #], but will automatically activate as soon as you hang up/power down the old phone).
I wish I remembered the guys name... might be Brian? He was so helpful! After screwing around with my phone for a whole day, I'm glad it was finally activated!