On the PHPRiot.com site today there's a new tutorial posted covering an alternate method for uploading files - using Ajax to help monitor the progress of the file upload.

In this article we will develop a solution that will allow users to upload a file from their computer using HTML forms. We will then determine the progress of the upload while it is in progress using Ajax, and display the status to the user.

They chose the prototype library and the APC extension for PHP to make their code work. The basic idea is, through a feature of APC, the script can receive a progress measurement back from the server. This is handed off to the Javascript (Ajax) functionality that then updates the progress meter to reflect the change.