Irssi is a terminal based IRC client for UNIX systems. It also supports SILC and ICB protocols via plugins.
Modular realtime chat client supporting IRC and SILC protocols. Supports multiple servers, themes, perl scripting and plugins.
Useful links:
- Irssi - The client of the future: The irssi home page
- [Howto] Setup irssi and join #ubuntu on Freenode: Using irssi with SSL/SASL to connect to Freenode
- Irssi - Arch Wiki: Details on irssi setup and configuration in a great Arch wiki page