Experienced PHP developer needed - Easy Project

Hiring ASAP, Do not send spam bid without reading the full desc... I am in need of an experienced PHP developer for the following tasks: I am describing as much as possible, this doesn't mean this is a huge task! bid amount must be reasonable, will hire for multiple project-ongoin project... Mainly what i need is a script or PHP file where it will mimic PayPal IPN... read below... let me explain... *** Suppose, I have two websites, say "Site-A" & "Site-B" Site A: =========== 1. In site-a, if a user send money anyhow, i search for this user using "user name" in database and add money to his account. user then post ads on site-a using that money or whatever. 2. So, in site-a, user have an account where there is a unique "user name" and email address associated for each user. Site B: =============== 1. user visits site-b, they enter their email address on site-b. and SITE-B asks "Site-A" if the email address is registered on "SITE-A"? if return result is yes, then site-a tells site-b the "user name" associated with the user, site b grabs that and go forward and record that in site-b's order database. 2. When i press a button called "Complete Order", site-b tells SITE-A that this "user name" associated account should be given $--.-- in its account. Site-A verifies the request if its made from the RIGHT domain & IP or not. If the add money request is valid from a pre-defined domain ONLY, Site-A process the request and add the requested amount + (existing amount, if any) = total amount in that specific users account in database. ====================================================================== ### NOW, SITE-B can do it if the request comes from PayPal not "site-b". If a user wants to add money to his account, he can write a amount in input box, click on "pay with PayPal", they then taken to paypal page along with his account info and if the paypal payment is successful, paypal IPN tells the above and site-a grabs that and do the process automatically. ### Instead of paypal auto system, i want to do it manually from "site-b", i press a button, site-b tells site-a to do the process and site-a do it. Let me know if you have any questions, I am in need of a PHP developer to work on THIS project + other modification on this same website if the price is right.