Hello, I am building a simple little script that will allow visitors to buy an image from me. I have no idea how paypal's IPN works, and I couldnt figure it out from their site. How do I verify that a user has paid? Are there any tutorials?
Search Google, there's tons of stuff out there. One result from the first page is http://www.19.5degs.com/element/369.php
Also, you might find this thread useful: http://forums.digitalpoint.com/showpost.php?p=2050908&postcount=6