psyBNC is an easy-to-use, multi-user, permanent IRC-Bouncer with many features. Some of its features include symmetric ciphering of talk and connections (Blowfish and IDEA) It compiles on Linux, FreeBSD, SunOs and Solaris.
nwIRC is a small console IRC client for Unix systems. It works without third-party libraries and has been tested on Free/Net/OpenBSD, Darwin, Solaris, HP-UX, OSF1/Tru64, IRIX, AIX, Linux and Cygwin. Key features are multiserver/IPv6/DCC/modules support