how do you start adding ftp customers for an apache web server? i want the consumer to join up from normal web/script after which come with an FTP account setup on their behalf instantly.

I've come across the cPanel API, which is pretty decent, consider cPanel is expensive, i shouldn't apply it this project. I am also unwilling to use every other lisenced software program.

i wish to have the ability to get it done using spend/batch (or pure PHP, though that hardly appear plausible)

Well while you stated Apache is really a Web and never an FTP Server. But many FTP servers like e.g. PureFtpd offer MySQL authentication. So you just need to customize the authentication table with PHP to include new customers.