Add Phone Number to Checkout on OsCommerce site

A very small modification to an existing OScommerce store. On the checkout page display the existing phone number on file for a customer [if there is one] and allow the customer to update it. This is required as we need a reliable phone number to provide the shipping company with. The phone number also needs to be displayed on the order confirmation page and the customer needs to have the ability to change it there also. When the customer changes the phone number we need to update the stored number for the customer in the database also. We have a lot of OScommerce work to be done and are looking for a reliable, economical and talented developer who we could keep busy for a few months at least. So if you can do this small modification well and quickly we have a lot of additional work we can give to you.