SFBrowser is an open source application, built with PHP and jQuery, formanaging files online with an Ajaxed interface.
Besides listing files and folders, it can upload, delete, rename and preview them. Uploading can be accomplished via an Ajaxed or Flash-based uploader (queued multiple uploads, progress bar, canceling, selection filtering, size filtering).
The functionality can be extended with plugins. There are few ready-to-use ones like filetree and image-resize.