Centericq is a text mode menu- and window-driven IM interface that supports the ICQ2000, Yahoo!, AIM, IRC, MSN, Gadu-Gadu and Jabber protocols. Features include a view contact list as a lightbar-menu send/receive both messages and URLs, search users, view users' details, maintain your contact list directly from the program, have your own ignore list. hot
Pidgin is a multi-protocol Instant Messaging client that allows you to use all of your IM accounts at once. Pidgin can work with: AIM, Bonjour, Gadu-Gadu, Google Talk, Groupwise, ICQ, IRC, MSN, QQ, SILC, SIMPLE, Sametime, XMPP, Yahoo!, and Zephyr. Read more hot
Ayttm is an instant messaging (aka chat) client that provides all-in-one chat functionality for several major instant messaging services from one simple program. Ayttm "Contacts" allow you to refer to several accounts of the same person from a single contact name, making it one of the cleanest and simplest clients to use. Ayttm currently handles Yahoo!, MSN, Jabber, IRC, AIM and ICQ.
CenterIM is a fork of CenterICQ.
(commercial) DBabble is a powerful instant messaging and discussion server which allows users to send instant messages and attachments, have private conversations, and create/participate in private or public meeting rooms and discussions in real time.
ekg2 is an opensource IM client for Unix systems (Linux, *BSD, SunOS, Solaris, MacOS, X, BeOS). Source code is protected by GPL.
Everybuddy is designed to be an universal messaging client. Everybuddy has support for AIM, ICQ, MSN, Yahoo! and Jabber chat programs. It also has file transfer between other Everybuddy users, and planned support for file transfer to other users.
Funpidgin is a modified version of the Pidgin instant messenger application. It was made in response to the controversial auto-resizing textbox that was implemented in Pidgin. Current features of Funpidgin include manual resizing and the ability to turn off persistent window placement. Funpidgin's releases are meant to coincide with Pidgin's releases.
Gadu is an instant messanger application, designed to work with IM protocols popular in Poland (but not only). This is a plugin based application, even GUI ( which uses GTK+) is a plugin.
Senility is an Instant Messenger client for the GNOME Desktop. It will provide full integration into the desktop, and strive to support all of the available Instant Messaging protocols.
IMSpector is an Instant Messenger transparent proxy with logging capabilities. Currently it supports MSN, AIM and ICQ to different degrees. MSN is the principle protocol, as it is these days the most popular.
KiT is a program that let's you see people that are online, send messages to them and do lots of nice things.
Kopete is an instant messenger supporting AIM, ICQ, MSN, Yahoo, Jabber, IRC, Gadu-Gadu, Novell GroupWise Messenger, and more. It is designed to be a flexible and extensible multi-protocol system suitable for personal and enterprise use. The goal of Kopete is to provide users with a single easy-to-use way to access all of their instant messaging systems. The interface puts people first, and is integrated with the system address book to let you access your contacts from other KDE applications. IM can be intrusive, but Kopete's notification system can be tuned so that only important contacts interrupt you. Read more
Milkbone is a GUI instant messaging client written in Perl. It is designed to be compact (190K distribution) and to give users the ability to create powerful extensions and to be completely customizable.
naim is a console client for AOL Instant Messenger (AIM), AOL I Seek You (ICQ), Internet Relay Chat (IRC), and The lily CMC. naim includes unique features like zero-configuration peer to peer encryption, automatic message queueing, and incoming message modification (to correct common spelling mistakes and expand common abbreviations; see /help filter).
naim also includes powerful dynamic module support, allowing developers to modify all major aspects of naim's behavior.
SIM-IM (SIM Instant Messenger) is a free software package licensed under the GNU General Public License (GPL). SIM provides an plugins-based instant messenger with support for various protocols. Based on the Qt library it works on X11 (optional with KDE-support), MS Windows and MacOS X.
Yeemp is a multiprotocol instant messaging program. It currently runs on Linux and FreeBSD. The Yeemp client supports the Yeemp, ICQ, and AIM protocols.