Hosting signup and billing system as well as domain registration.
Currently support enom.com (domains) and 2checkout.com & paypal.
Set montly, quartely, yearly reccuring transactions at 2CO and paypal.com
Plesk6, Cpanel/WHM . Lot changes in admin area,
many new options, more control now !

http://www.alyakweb.com/signup-script.shtml