GroupServer is a Web-based mailing list manager designed for large sites. It provides email interaction like a traditional mailing list manager but also supports reading, searching, and posting of messages and files via the Web. Users have forum-style profiles, and can manage their email addresses and other settings using the same Web interface. It has supports features such as Atom feeds, a basic CMS, statistics, multiple verified addresses per user, and bounce detection, and is able to be heavily customized.
GroupOffice is a groupware suite that takes your office online, implementing online collaboration and CRM. It allows you to share projects, calendars, files and email online with co-workers and clients. It is easy to use and fully customizable. It also features synchronization with PDAs and Outlook.
EGroupware is a Web-based groupware suite. It contains many modules, including Calendar (personal calendar and group scheduling, notifications and alarms), Mail (IMAP only), InfoLog (todos, notes, and phone calls linked to contacts/CRM), Contacts (an address book for storing and sharing contact information), ProjectManager, Tracker (bug or incident tracking), TimeSheet, SyncML, CalDAV & CardDAV support, and SiteMgr content management
Oliver (formerly "WebShare") is a PHP-based FTP front-end, released under the GPL. It allows people to access files normally only available via FTP, effectively providing users with a complete Web-based file management system that, if SSL is enabled on the Web server, uses a single secure connection. This makes it far simpler to use through a firewall. At present, Oliver has only been tested with ProFTPd and PureFTPd but it should work with many others.
BaconMap allows you to visualize interdependent IT resources. It helps you answer the question, "What fails when this fails?" BaconMap is an IT resource manager and a wiki Web program. The application allows IT staff to map interdependent resources to each other to create a visual representation of the network.
BytesFall Explorer (bfExplorer for short) is a Web-based file manager. It allows you to upload, download, view, edit, copy, move/rename, and change permissions of a single file/directory or a group of files/directories. It's also possible to create files and directories and execute shell commands. An SQL engine is used to store the users for the authentication (currently MySQL and PostgreSQL are supported). It has an interface similar to Windows Explorer.
Server-side FileManager is a Java servlet which implements FileManager. You can use this servlet for remote site management: upload/download files, copy/move files, edit files, etc. Its main advantage is that it uses only the HTTP protocol for access to your host, which allows it to work through most firewalls.