AfterX.net

A client is a user-side software used to enable the user's computer to connect to an IRC server of a network and provides the user with an interface showing text messages as they appear, who is in the channel and what the channel topic is, amongst other things.

A list of known clients are:

Windows:
mIRC - http://www.mirc.com
XChat - http://www.xchat.org
Klient - http://www.klient.com

Linux:
XChat - http://www.xchat.org

Unix flavours:
BitchX - http://www.bitchx.org

Apple Macs:
IRCle - http://www.ircle.com

Amiga:
AmIRC (OS4) - http://www.vapor.de
WookieChat (OS4) - http://amigaworld.net/modules/news/article.php?storyid=2768