The AMC Mail Client is a mail client striving to be a robust, fully gnome-compliant mail reader. However, the AMC Mail Client differs from other mail clients in that it attempts to utilize existing tools for mail retrieval, sending, and filtering, (fetchmail, sendmail/smtp, procmail). By not going through the process of reinventing the wheel, the AMC Mail Client starts out as a fully equipped client that inherits all of the features of these existing tools.
Evolution is the GNOME mailer, calendar, contact manager, and communications tool. Evolution represents the next step forward in GNOME applications. The tools which make up Evolution will be tightly integrated with one another and act as a seamless personal information-management tool.
Gabber is a Jabber client for GNOME. Jabber is a flexible distributed Open Source instant messaging system. It also happens to allow communication with other instant messaging systems, such as ICQ, AIM, Yahoo!, MSN, and even IRC. Gabber aims to implement quite a bit of Jabber's functionality while remaining easy to use.
GMailWatch is a GNOME Panel Applet that displays a summary of incoming mail (sender/subject) rather than just an icon. It's similar to the old xmailwatcher utility (and uses some of the same code), and is also based upon mailcheck (of gnome-core). The user can change the size of the panel applet.
KBiff is a KDE "biff" or new mail notification utility. It is highly configurable but very easy to use and setup. It supports session managment (it "remembers" the last state it was in before you logged off) and can be docked into the panel. It has support for mbox (Unix-style), maildir (qmail-style), mh, POP3, IMAP4, and NNTP mailboxes.
kicq is an ICQ client specifically designed for the KDE desktop. It has a simple, clean interface very similar to the original Windows ICQ client, and includes all of the most commonly used ICQ features such as messaging, real-time chat, and file transfer. It features complete message history, a New ICQ User registration window, multiple ICQ accounts, SOCKS5 proxy inline support, configurable sound events, Cyrillic koi8-r/cp1251 recoding, and support for the ICQ UDP v5 and ICQ TCP v2 protocols.