FSGuide is a great two-panel file managment tool that helps performing file operations through the web. Features: user authentication, access control lists, 2-panel layout, bookmarks, filelist, file uploader (and run any application after upload!), bandwidth-controlled download, advanced select dialog, file editor (even binary!), file viewers (highlighting HTML and PHP code), multilingual support + a lot more more! It's written in PHP, it needs no database backend. Check the screenshots at the website!