As stated on the mIRC website (mirc.com) here

IRC programs for other OS's
JPilot java applet http://www.jpilot.com
IRCle for Macintosh http://www.ircle.com
Irc CE http://www.movsoftware.com/ircce.htm
IRC for WebTV http://www.irchelp.org/irchelp/misc/webtv.html
IRCii for UNIX http://www.irchelp.org/irchelp/ircii/
BitchX for UNIX http://www.bitchx.org
Other IRC clients http://www.valinor.sorcery.net/clients/

Cobra^