Horde Groupware Webmail Edition

Horde Groupware Webmail Edition is a free, enterprise ready, browser based communication suite. Users can read, send and organize email messages and manage and share calendars, contacts, tasks and notes with the standards compliant components from the Horde Project. Horde Groupware Webmail Edition bundles the separately available applications IMP, Ingo, Kronolith, Turba, Nag and Mnemo.

Features

• IMAP and POP3 webmail client
• Message filtering
• Message searching
• HTML message composition with WYSIWIG editor
• Spell checking
• Built in attachment viewers
• Encrypting and signing of messages (S/MIME and PGP)
• Quota support
• Keyboard navigation
• Full character set support for folders names and email messages
• Conversation view of all messages in a thread
• Folder tree in left menu pane
• Message previews in mailbox view
• Downloading of message attachments in a ZIP file
• Fetching of messages from external email accounts
• Flexible, individual alias addresses
• IMAP folder subscriptions
• Shared IMAP folders
• Graphical emoticons
• Support for mailing list headers
• Forwarding of multiple messages at once
• Attachments sent as links

http://www.horde.org/webmail/