Creating my own Affiliate Links

Ok, so I have a website where I'd like to offer my own affiliate program (i use wordpress). Anyone have any pre built php scripts to do this kind of thing?

My current though is to automatically generate an affiliate link for every member. ex: www.mysite.com/?ref=7902

So that referral number gets automatically populated into the registration field once they do that. Whats the easiest way to get that done, by cookies or using a session variable?

I believe there are some WP plugins that will do it all for you. Like WordPress Affiliate Platform Plugin, which is $50, but surely there's a free, or "free" one somewhere. We use cookies for all of our tracking. Super easy and works well, but that's all I've ever used.

Well since you're using wordpress I recomend you just look at all the plugins they have available.

here's a google search for what you're looking for

http://www.google.ca/search?q=wordpress+affiliate+tracking&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

ok well heres a question.. how do i retrieve the value ref=7902 to autopopulate a form field with that value 7902 as the default?

nevermind stupid question, was having troubles because it was an iframed regstration page