are there any free scripts available which would allow me to have an affiliate program where people can sign up and for every sale they make they get some money. I want there to be stats and a login panel for the user so that they can check their earnings. I know oscommerce has a module for this but i've already made my site and i dont want to use oscommerce.

contacts:
email: fantasian@optusnet.com.au
msn: ex_calibur69@hotmail.com
aim: minhn1987

thanks