XMail Server Lite is an open source & free mail server with an Ajaxed webmail bundled to it.

It is compatible with Window & Linux OSs with 2 different installers provided.

The server is capable of managing SMTP/ESMTP & POP3 protocols with web-based administration panel.

It supports unlimited domains/users including virtual domains & aliases.

XMail Lite also offers anti-virus integration, bayesian filters (for spam protection) & a logging functionality of all the activities.

The Webmail Lite can display folders/nested folders, has an address book, multilingual & much more.

Tip: The webmail can be downloaded & installed as a standalone product too (from here).

T-dah is a free PHP webmail application which is built from the well-known Uebimiau script & offers a slick interface.

It can be up & running in a few minutes on any PHP (4 or 5) enabled server as no database is required.

The application uses the POP3 protocol & can be configured to use SMTP, PHP mail, Sendmail or Qmail for sending e-mails.

T-dah comes with several modules like:

• event calendar
• group chat
• addressbook
• folder management

It uses TinyMCE WYSIWYG editor for creating new e-mails, has an integrated search & can be translated into any language with the "language files" support.