update shipping options in custom site

This task is to update the shipping in a custom ecommerce website, replacing the current internally generated shipping estimations with realtime shipping quotes from UPS and USPS and UPS address verification. The site is a custom but very simply php/mysql site with a few javascript functions. It currently uses only simple easy to understand function calls with no object oriented functionality. I'd prefer your additions to existing code be documented, straightforward, and easy to alter as the site may someday include other shipping companies and options. I believe I already have the keys and passwords that will be requred so work could begin immediately. Currently US destination addresses are given the option of choosing UPS ground or USPS priority shipping or just choosing the cheapest option. Currently I use lookup tables in a shipping database to determine these amounts. These tables will be replaced with realtime quotes with a small handling fee added on. No additional shipping options are desired at this time as I would rather encourage those who want to ship rush, to call instead of using the web site. Non US customers are given the option of air mail parcel post or economy parcel post. These numbers as well as the destination country are also currently pulled from the shipping database. Information currently coming from this databse will be replaced with realtime information from the USPS website. The task involves: Allowing me to ftp needed files to your site and backups of mysql databases to your site. Setting up an copy of my site on your local server for development. Following UPS and USPS guidelines to integrate these solutions. Communicating any options to me so I can make decisions as needed. Make any needed changes to mysql tables and databases and telling me what you did so I can match them on site. Make any needed design changes to [login to view URL], [login to view URL] or other files as needed to show shipping options, and to notify users of invalid addresses and whatever else is needed. Let me test implementation to the site on your server. Tell me what files you created or changed and let me pick them up from your site after payment.