Algorithm for retrieving inventory from point of sale software

i need an algorithm for getting inventory from any or most point of sale software. I need it to retrieve with the owners permission the inventory data so it can be stored on a server for a website that we will have designed to cater for a local search engine. if you have actually read the requirement can you add the word ( gwylow) at the top of your reply heading so i can distinguish who has read the requirements :)