Amazon's phone-sales business unit has added a HOWTO on number-portability, and a service to help you keep your number when you change mobile carriers.
Transferring your cell phone number is easy when you order from Amazon.com. You won't have to wait in line at a store while your number is transferred from your previous carrier to your new one. And, in some cases, you will be assigned a temporary phone number for your new phone so that you can use it until your transfer is completed (you can even forward your calls from your current phone to your new phone in the interim). Best of all, when you buy a cell phone from Amazon.com and transfer your number, you will still qualify for all of our great rebates and discounts.
(via MobileWhack)