Hi folks. Does anybody know of a module that does the following:

I want to give customers points (a % of total order sum) so that they can use it later to pay for more items on my site when they have earned enough points. When they "inform" or "tell" a friend about my page, and his friend pays his first order, both the new customer should get his points, and the friend that told him about the site should receive points.

Kind of an MLM system for getting more customers. is this available?