On the WebSpeaks.in site, there's a recent tutorial posted showing how you can extract the contents of a zip file from inside a PHP application.

Sometimes you may want the users on your site to upload the zip file and then check what are the contents of that zip file. In this article I will tell you how to extract the contents of the zip file. I temporarily extract the zip files to a directory and then delete it afterwards. You can chose to keep the extracted content if you want.

The tutorial walks you through the code, showing you how to use their "ZipArchive" class to grab the file, extract the contents and display a list of the "child files" inside it. You can see a live demo of it in action or just download the source and dive right in.