I wrote a few different scripts that auto create email accounts in cpanel. Where a visitor/user/customer can go to your website and create an email address and it will be all automated via cpanel. Where you do not have to login cpanel to create email address. All secure with image verifications too. Spam blockers....you name it.
This script can be uploaded to your ftp and just do a little editing to match your website. I have also made step by step tutorials for this also.