Automated account setup and Fantastico install

Is there a way that I can have a customer submit a form, and it automatically create the account and install one of the programs in Fantastico (like Drupal, Joomla, Wordpress, Soho, etc)? I would like for customers to just make a few choices, submit payment information, and roll immediately instead of me having to set everything up for them manually.

I know there HAS to be a way, since all of the larger hosting companies out there seem to do it... I just don't know how. I'm sure that I can write a script to do it, I'm not asking for that (although I'll take it if it's readily available); I just need to know how to tie my script into the setup.

TIA,

Jason