The Zip Processor PHP provides industry-standard Zip archive functionality. It is designed to be easy to use. You can pack/unpack a file or folder without a single line of code. If you need to create or extract Zip files automatically, this extension is for you. Combined with Pure PHP Upload 2, your users can upload Zip files directly! Use form fields to allow the user to select his/her own files to be compressed in a new zip file for direct download. You can even Zip a complete folder to, for example, create a backup of your site.

You don't need to write any additional code or install server components; it runs on PHP 4 and PHP 5.