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.
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.
licqweb is a Web frontend for licq. It interfaces with the Remote Management Service plugin and uses AJAX to provide real-time communication. It is useful for people who use IMs from multiple locations and want a 'centralised' application that means no more logging off and on, consolidates chat history to the one location, and prevents problems where messages are missed because another IM client received them.
ImageIM is a plugin for Gaim that lets buddies send screenshots to each other via HTTP. Users can simply click the ImageIM button, select a portion of the screen, and then send their buddy the image. If the buddy doesn't have ImageIM, they will receive a link pointing them to the image.