Sylpheed - Mail User Agent based on GTK+.

Sylpheed is an e-mail client (and news reader) based on GTK+, running on X Window System, and aiming for: Quick response, Graceful, and sophisticated interface, Easy configuration, intuitive operation, Abundant features. The appearance and interface are similar to some popular e-mail clients for Windows, such as Outlook Express, Becky!, and Datula. The interface is also designed to emulate the mailers on Emacsen, and almost all commands are accessible with the keyboard. The messages are managed by MH format, and you will be able to use it together with another mailer based on MH format (like Mew). You can also use fetchmail or/and procmail, and external programs on receiving (like inc or imget).