centericq is a text mode menu- and window-driven IM interface that supports the ICQ2000, Yahoo!, AIM, IRC, MSN, Gadu-Gadu, and Jabber protocols. It allows you to send, receive, and forward messages, URLs, SMSes (both through the ICQ server and email gateways supported by Mirabilis), contacts, and email express messages, and it has many other useful features. An internal RSS reader and a LiveJournal client are also provided.
BitlBee allows users to talk to people on the major instant messaging and microblogging networks (including MSN, Google Talk, AIM, and Twitter) from within any IRC client by emulating an IRC server. Virtual channels are created with all of the user's contacts in them, who can be talked to in the channel or in a query. Also, one can participate in group chats and chat rooms like they were normal IRC channels.
climm (CLI-based Multi-Messenger) is a portable, small, yet powerful console-based ICQ and XMPP client. It supports password changing, auto-away, creation of new accounts, and other features that makes it a very complete yet simple client. It is able to send and receive messages from the ICQ network, list users that are offline and online (including their online status), search for users by email address, and look up basic (name, UIN, email) information. climm was formerly known as mICQ.
AutoProfile is an extension to Gaim that allows users to create customized away messages and profiles using dynamic "components" that automatically update on a regular basis. Generated text can include song names from XMMS, Winamp, iTunes, or Windows Media Player, snippets of Xanga and LiveJournal posts or other RSS feeds, statistics regarding saved conversation logs, a countdown/countup timer, fortune quotes, computer uptime, the contents of a Web page or a text file, the output of a program, and timestamps. A large number of options allows users to fully customize the program as they see fit.
OpenGaim is an instant messaging or "text chat" client capable of communicating over many protocols, including Jabber, AOL Instant Messenger (AIM), ICQ, MSN Messenger, Yahoo! Messenger, Internet Relay Chat (IRC), and more. It is a loose relative of the Gaim project and contains much of the source code in Gaim itself. However, OpenGaim aims to provide quicker releases to fix major problems, and advanced customization options and features not available in Gaim.
The Off-the-Record (OTR) Messaging proxy is a multi- platform proxy that allows you to have private conversations using the AIM client of your choice. It provides encryption, which prevents someone who intercepts your instant messages from reading them, authentication, which ensures that the correspondent is who you think it is, and perfect forward secrecy, which ensures that no previous conversation is compromised if you lose control of your private keys.