dxirc is a easy-to-use yet capable cross-platform IRC client. Among its notable features are flexible configuration, a fully customizable look independent of system-wide settings, multiple server support with optional automated joining of selected channels, and the ability to connect via SSL.
ircproxy is an Internet Relay Chat Proxy, which works as a layer between your IRC client and the IRC server. It features bouncer capability and has more features, flexibility, and configuration options than other tools. It also includes an option to use the system password list instead of requiring a separate password database.
Joker the IRC bot is a PHP class designed for quick and easy IRC bot construction. This base class contains methods that can be executed from your plugins. It has built-in flood protection, timers, and a powerful plugin system that allows you to reload plugin classes on-the-fly, without restarting the PHP console or disconnecting from the network.
dircproxy is an IRC proxy server ("bouncer") designed for people who use IRC from lots of different workstations or clients, but wish to remain connected and see what they missed while they were away. You connect to IRC through dircproxy, and it keeps you connected to the server, even after you detach your client from it. While you're detached, it logs channel and private messages as well as important events, and when you reattach it'll download those logs to you using ordinary IRC protocol.
envbot is an advanced modular IRC bot coded in bash. Features include SSL, IPv6, modularity (with several good modules already), transport modules (including OpenSSL, GnuTLS, netcat, etc.), loading/unloading/reloading of modules at runtime, rehashing configuration at runtime, advanced access control, and much more.
Vayala is a multi-purpose chat client for developers. It offers a platform and an easy to use Eclipse plugin. Based on multicast technology, each client is automatically connected to one chat client network without a central server or much configuration or installation effort. You add the Eclipse view, and you are connected to your colleagues. In addition to basic chat functionality, you can also exchange files, graphics, and much more.
PircBot is a Java framework for writing IRC bots quickly and easily. Its features include an event-driven architecture to handle common IRC events, flood protection, DCC chat, file resuming, ident support, multiple servers, and more. Its comprehensive logfile format is suitable for use with pisg to generate channel statistics. Full documentation is included, and the Web site contains a 5-minute step-by-step guide to making your first IRC bot.