I would like to set up an offsite registration form and processing script.

The registration form domain is sharing a server with the main Joomla/CB website, so accessing the database is no problem. I could certainly write a basic form and script requesting the correct information and adding it to the database, even sending a user a confirmation email, but it would not go through the full process, email verification, etc.

Is there a way to set up registration to a Joomla/CB website from another website? They will not let me use an iframe to house the form from the original site.

Any help or pointing me in the direction of the correct documentation would be greatly appreciated.