On the IBM developerWorks site today, they've posted Part 3 of their series "Develop apps with Web services and the eBay SDK", this time, focusing on building it with PHP5.
Create applications in PHP5 that interact with eBay through Web services. Almost half of eBay's transactions occur through its Web services platform. In this tutorial, you'll acquire a solid understanding of the mechanics of the eBay XML API and learn how to use the Services_Ebay PHP extension.
To get up to speed on the project, you might want to check out Part 1 and Part 2 (thought they're not dealing with PHP). You'll also need an understanding of what XML is and how it works to get the most accomplished with the web service. There are ten pages of information here, and they don't skimp on any of the details - there's tons of code and XML examples to get you familiar with the whole process.
To check out the full tutorial, head over here...