Convert VB mailscript to PHP

Hi Folks, My client has re-thought their needs for this project and has decided to run their visitor input form and HTTP post to remote server all OUTSIDE of the WordPress framework, so WordPress-compatibility is not an issue. We will be mounting the Visitor input form, the PHP API post script, and the confirmation page on an HTTPS (secure socket layer) sub-domain of our main website. We will handle the Visitor form, which will POST its content to a PHP SCRIPT that you will create for us, based on the current VB script which we are attaching to this project.  This script takes the visitor form input and assembles the POST information in appropriate syntax to be sent to the MyEmma Remote SignUp API. So ALL we need is a PHP SCRIPT that will handle the post input from our visitor form and send it successfully to MyEMMA as our current VB script does right now. This script should be a script that will run on a secure server and will be secure enough in itself to prevent hackers from highjacking the form processing.