[Phpwm] Paypal Integration

[pete graham]

I need to implement a facility where a user on a site can request
another user to pay them some cash via paypal (it's a payments
reminder facility). I have no experience using paypal and was
wondering what the best route to take with this is.

I have been looking at
https://www.paypal.com/IntegrationCenter/ic_home.html but really don't
know which of these solutions will fit my needs best.

Also out of curiosity does anyone know what the backend technology
that Paypal runs on, or is it a big secret?

Pete