SeaMonkey : Web-browser, advanced e-mail and newsgroup client, IRC chat client, and HTML editing made simple -- all your Internet needs in one application.

Mozilla’s Thunderbird email application is more powerful than ever. It’s now even easier to organize, secure and customize your mail.

Gravity : Open Source Usenet News Reader for Windows.
Gravity is a full featured Windows Usenet online/offline news client with an extensive feature list. Gravity has been a popular news reader since 1996. Numerous features were added over the years. Gravity originally started as shareware, and later as freeware. It is now open source.

Mahogany is an OpenSource cross-platform mail and news client. It is available for X11/Unix and MS Win32 platforms, supporting a wide range of protocols and standards, including SMTP, POP3, IMAP, NNTP (including SSL support for all of them) and full MIME support.

Magic Mail Monitor (MMM) is a free POP3 mail monitor with multiple accounts support. It sits silently in your system tray, and notifies you about new messages in your mailboxes. Then you can preview messages and delete unwanted mail in order to avoid spam and viruses.
To help you fight spam, save time and traffic, MMM offers configurable filters, friends list, partial loading and other easy to use tools.

RoundAbout is an arbitrary name chosen for this project with the aim to deliver a modernized version of Phoenix Mail

AmphetaDesk is a news aggregator.

KookieJar is a program for Windows 95, 98, ME, 2000 and XP which generates signatures you may use with your favorite email or news program. A signature is a small piece of text, automatically attached to every email message or newsgroup posting. It typically includes a random quote — a so-called tagline (a sample tagline file is included with the program).

POPFile automatically sorts your messages and fights spam.

Outclass: Mail Classification for Outlook with POPFile