Gday Frank
I have recently linked Paypal for annual registrations. After you setup an account the hardest part was finding which boxes in the PayPal site to tick and I am still learning to understand that. However once that is done you are then provided with some HTML code which I pasted into the Browse where my users registration and useage details are displayed. I located it after(form) and developed a condition to display when registration was due in 30 days.
It would be much easier I suspect if the Paypal site was using NetTalk
John