CKFinder for PHP

From Frederico Knabben: CKFinder is a powerful and easy to use Ajax file manager for Internet browsers. Its simple interface makes it intuitive and quick to learn for all groups of users, from Internet beginners to advanced professionals. It features quick responses, folders tree navigation, quality image thumbnails, making it quick to find things, multi-language support with automatic user language detection, context-sensitive menus for files and folders, multiple file uploads with a progress bar, drag-and-drop support for copying and moving files between folders, store files in private folders, also outside the document root, and all uploaded files are checked according to the rules set by the developer.