PHPBuilder.com has a new tutorial posted to help you create a more complete file upload solution for your web application.

Every time I've written some code to upload a file, either to send it off as an email attachment or as an image for some dynamic content piece, I've always meant to write a few functions so I don't have to write the code again. [...] So I *finally* sat down and wrote this script.

They go through the settings first including the path to put the files in, types that are known and the ones that are allowed. Then its on to the code that creates the form field and handles the upload and validates it. You can download the code for the tutorial here.