CGI:IRC is a Perl/CGI program that lets you access IRC from a web browser, it is designed to be flexible and has many uses such as an IRC gateway for an IRC network, a chat-room for a website or to access IRC when stuck behind a restrictive firewall.
Lambdabot is a Haskell development tool, written in Haskell. It operates as a command line tool, embedded in an editor, embedded in GHCi, via internet relay chat and on the web. More information is available at the Haskell wiki.
BitlBee brings IM (instant messaging) to IRC clients. It's a great solution for people who have an IRC client running all the time and don't want to run an additional MSN/AIM/whatever client. BitlBee currently supports the following IM networks/protocols:
Qnext comes with a built-in and easy-to-use IRC client that connects into IRC servers around the world on the IRC network. This gives you access to thousands of user channels and millions of other users. No need for others to have Qnext.
Quassel IRC is a modern, cross-platform, distributed IRC client, meaning that one (or multiple) client(s) can attach to and detach from a central core -- much like the popular combination of screen and a text-based IRC client such as WeeChat, but graphical. In addition to this uniqe feature, we aim to bring a pleasurable, comfortable chatting experience to all major platforms (including Linux®, Windows®, and MacOS X® as well as Qtopia-based cell phones and PDAs), making communication with your peers not only convenient, but also ubiquitous available.
And the best of all: It's free - as in beer and as in speech, since we distribute Quassel under the GPL, and you are welcome to download and see for yourself!
M. Knoll, M. Helling, A. Wacker, S. Holzapfel, и T. Weis. Proceedings of the 5th International Workshop on Collaborative Peer-to-Peer Systems, COPS09, organized at the 18th IEEE International Workshops on Enabling Technologies: Infrastructures for Collaborative Enterprises, WETICE 2009, Groningen, The Netherlands, (June 29th - July 1st 06 2009)-July 1 st.