Ingenico i5100 / i3300 Linked to Web based service

Hi, I hope the following idea/project can be put into practice. We are currently building a web based till system. My problem is the credit card machine, we would like to be able to link an Ingenico/ Verifone/ ... terminal preferably up to this so that you can feed the amount to take straight from the web interface to the card machine or when you put a card in the machine it notifies the web service. Something along these lines. So we need something that can integrate with the machine via the web, so basically when you press buttons it does stuff, or you can give the machine a static IP and feed commands to it. I have no idea how these machines work but would love to have a way of communicating with it via a web interface or have commands i can send to it so that I can capture the auth data etc maybe too. If you would like to have a crack at this or have any thoughs etc, please get in touch. Its not mega urgent but is something i would like to develop in the near future. Thanks.