Mollify is an open source web-based file manager, built with PHP & GWT, that can control files hosted in a web server or hosting account.

It has a simple, intuitive & Ajaxed interface that also supports multiple languages.

The application is multi-user (users & user-groups) where a file-level access can be set.

File actions & directory actions can be completed quickly from context popup menus. It is also possible to download files/folders in zipped format.

Mollify can upload multiple files at once & enables to list the contents with sortable columns.

A unique feature offered is the ability to define aliases for folders in order to hide the real folder structure for security purposes.

The interface is totally customizable with CSS. Also, integration of the application with other products is possible as the frontend & backends are independent (they communicate with HTTP/JSON).

Downloadify is a lightweight JavaScript + Flash library for generating files on the browser & saving them without any server requests.

It uses Flash 10's ability to generate files on the client-side & trigger a save to the user’s computer.

It is very ideal for using on small-sized files that were already loaded like vCards, color codes, custom codes, addresses, etc.

It only requires swfobject & doesn't need any other JavaScript library to run.

IZWebFileManager is a powerful open source file manager control for ASP.NET 2.

It works very similar to Windows Explorer & can copy/move/rename/delete (multiple) files and folders.

The file manager supports:

• file upload
  
• displaying hidden files and folders
  
• drag'n drop
  
• right-click context menu
  
• keyboard controls
  
• & more..
  

IZWebFileManager has a multilingual interface & offers a permission control where any feature can be disabled.

Uploadify is a jQuery plugin for implementing single + multiple file uploads easier & better.

It requires Flash (which completes the upload) & a server-side file in any language (. PHP one is included) which processes the uploaded file.

The plugin offers various options to control & customize the upload interface like:

• files types
• max. number of simultaneous files
• auto or manual start of uploads
• size limit
• callback on every step (onSelect, onCancel..)
• & more..

And, implementation is as simple as any other jQuery plugin; just by calling a function.

FileManager is a MooTools-based file manager that allows you to control your files-folders with style.

It runs in a modal box & with an Ajaxed interface, helps:

• browsing files/folders quickly
• rename, delete, move (with drag’n drop), copy (drag + hold CTRL) and download files
• view detailed reviews of images, text-files, compressed-files or audio content
• Option to automatically resize big images when uploading
• Use it to select a file anywhere you need to specify one inside your application’s backend

FileManager uses the FancyUpload3 script that is soon to be released for good-looking file uploads.

And, it can be easily integrated with TinyMCE as well. For a standard demo, click here & for a TinyMCE integrated demo, click here.

P.S. Thanks very much to David Walsh for the suggestion.

XtraUpload is a free file hosting script for anyone willing to create a service similar to Rapidshare.com or Megaupload.com.

It is written in PHP (CodeIgniter Framework) & uses MySQL for storing data.

The script is also an e-commerce platform as you can offer both standard-free & premium-paid plans where payments can be handled via PayPal, 2Checkout, Authorize.net, Moneybookers & more. All are integrated.

It has an e-mail validated signup system where users can:

• upload multiple files
• create & password protect folders
• rate files
• share links via e-mail & more..

And, with a powerful administrator screen, you can:

• restrict downloads with:
  • amount of allowed MB per hour
  • defining concurrent download limits
• create user groups & define limits for each user group
• add/manage servers (multi-server support)
• manage subscriptions
• enable/disable captcha & much more..

Besides being a complete file hosting platform, XtraUpload’s code is a resource for anyone into CodeIgniter Framework covering most of the features a web application have.

AjaXplorer is a free Ajax file manager with powerful features & an user-friendly interface.

It is built with PHP (4 & 5) & does not require any database to run. Just an upload & use solution.

Some great features of AjaXplorer:

• File/folder actions: rename/copy/move/delete/download
• Multiple file upload with progress bar
• Edit text files (syntax highlighting for js, php, html, java, sql & perl)
• Images can be previewed & viewed as a slideshow
• Mp3 files can be listened without downloading them
• Flash videos can be viewed
• ZIP files can be browsed & extracted
• Bookmark system for reaching to the desired files easier
• Multilanguage
• Recursive search & more

AjaXplorer has a multi-user environment. The admin can create new users & assign the permitted directories/rights to those users.

The application also offers a high-level of usability with drag’n drop support, keyboard shortcuts, list / thumbnails views & ability to select multiple file / folders.

Simple Directory Listing is a PHP script that works as an online file manager.

It is only one file, just upload & use, and requires PHP to run.

The script can work in read-only or full mode and can be limited to manage a folder.

Besides the functions of a standard file manager script, it also has a FTP layer that makes it possible to connect to remote hosts.

And, the script has RSS support.

Such scripts are very useful when you want to make "files of a project"  reachable by customers where FTP usage may be limited or seem advanced from the eyes of the customer.

eXtplorer is a free Ajax – PHP file manager built with Ext JS library.

It can function both as a file manager for local files and a web-based ftp application.

Editing files with syntax highlighting, extracting archives & user management with permission levels are great features of this application.

Some features of this Ajax file manager are:

• Copy & move files and directories by drag&drop
• Dynamic directory tree with on-demand loading of subdirectories
• Rename, delete or create new files and directories
• Upload or download files just as you like

eXplorer is also available as a component for Joomla! and Mambo.

Flickr’s Flash file uploader is one of the most functional uploaders a developer can think of.

It supports:

• Multiple file selection in a single "Open File" dialog.
• File extension filters for easier selection.
• Upload progress tracking.
• Filename, size, date created, date modified, and author can easily be extrated.

This flash file uploader is avaliable as the YUI Uploader component.

You can also include additional data in the upload POST request.

And, upload component provides faster file upload on broadband connections due to the modified SEND buffer size.