125956 Membership Account Creator

I need a script that lets a user create an account using an email and password, they are given a web link which they have to give to 5 seperate people(i.p addresses/hosts - not same computer) before it gets activated OR the user can spend $5 at paypal, so the paypal ipn script(you can use a free one i dont mind - as long as it works) Password (when checked) should be md5 encrypted and should have password retrieval as well as change email address. ---- This script will be called from a desktop application to check whether account is active/logged in so the script needs to echo either "YES" responce "NO" responce "3 more people to go!" responce If you have better suggestions or ideas I would love to hear them :) ---- Summary 1) Account Creator/Checker 2) Generate Weblink that needs to be clicked on by 5 seperate people before account is active 3) Paypal IPN (you can use a free one, i dont care) 4) Username & Password Change/Retrieval I expect Installation instructions also.