SitePoint's PHPMaster.com site has a new tutorial today from Timothy Boronczky about handling file uploads in PHP. It's a pretty low-level introduction and is perfect for those new to PHP.
What do pictures in an online photo album, email attachments in a web-based mail client, and data files submitted to an online application for batch processing all have in common? They all rely on the ability to upload files across the Internet from the user’s web browser. Indeed, uploading files is an important feature of many of the sites and web-based applications we use on a daily basis. In this post, I show you how to add support for file uploads to your site using PHP.
He starts with the changes you might need to make to your php.ini configuration file (for allowing uploads and setting a temporary directory) and a basic "form" tag with the necessary "enctype" setting. The sample form includes a "file" type field that submits the file data to a waiting PHP script on the backend. The script looks for the submit (in the $_FILES superglobal) and, after doing some filtering on the name and content type, moves it to a new directory.