SFBrowser is an open source application, built with PHP and jQuery, for managing files online with an Ajaxed interface.
It returns a list of objects with containing the names and additional information of the selected files. You can use it, like any open-file-dialog, to select one or more files. Most inherent functionalities are also there like: file upload, file preview, creating folders and renaming or deleting files and folders.
The functionality can be extended with plugins. There are few ready-to-use ones like filetree and image-resize.
For a faster usage, there is a context menu and support for keyboard shortcuts.
It is a multilanguage application, new languages can be added by creating new localization files (English, Dutch or Spanish are already included).
P.S. It is also available as a WordPress plugin.