Affiliate Program

Looking for a simple affiliate program that will be installed on my server, that will allow clients to sign up as an affiliate, be given access to an admin. area where they can receive affiliate links and banners for 1 or more of my hosted sites. Most, if not all, of my customers are NOT website owners or very skilled in most Internet processes, so making it simple and clear are important. Banner option would be nice, but most important is the ability to quickly and easily access affiliate URL link to begin promoting various sites. System must be able to send confirmation e-mail with affiliate URL link included, along with other personalized tags. Payments to affiliates will be through PayPal or paper check. Would like to have the ability to add flat fee or % of sale. Allow for 2 tier affiliates, with affiliates getting a % or flat fee for referring other affiliates. Would also like to install this system on one website and use to run different affiliate programs on 7 of my sites (but use the same admin. and affiliate login area). So program should give me the option to add "groups" or "websites" with different products listed under each group with different affiliate payout amounts and percentages on each (and then produce different URL affiliate links depending on which "group" product(s) they would like to promote. Would like program to work with PayPal and [login to view URL] payment systems. Not sure how IPN scripts work with PayPal, but I am currently using a modified IPN script with PayPal with an autoresponder system that gives confirmation e-mails on orders and adds them to a specific listmail database (so I don't think I can change the current IPN in my PayPal settings). Not sure if that information matters, but wanted to make it known, if that is the system you were planning on using to track payments. Affiliate program will have look and feel of this site: [login to view URL] (which will become [login to view URL] once it propagates within the next 12 hours). Please, only experienced affiliate programmer's bids wanted.