Wikipedia:irssi is a popular IRC client, but since tg started developing irssi-psyc, it can turn into a native PSYC client.

git it from here:

git clone git://git.tgbit.net/irssi-psyc

• gitweb+clone: http://git.tgbit.net/irssi-psyc
• commit logs: psyc://x-net.hu/@irssi-psyc

Would be terrific if irssi-otr worked in combination with irssi-psyc.

See also OTR encryption, Typing, Icecap, http://www.irssi.org and perlpsyc in general.