IceChat IRC Client
IceChat is an IRC ( Internet Relay Chat) program designed to run on Windows 9x/Me/2k/XP/2003 and Vista. It is used to connect to IRC Servers and chat in channels with other IRC Users.
You can connect IceChat to an unlimited number of servers, all in one session (No need to start multiple copies of IceChat). You can do basic mirc scripting with IceChat, as well as use the Visual Basic Scripting (VBS) Engine. It can create custom popup menus, with the Popup Editor, or adding them with scripts, using the IceChat Editor.
Go to http://www.icechat.net/site/index.php?module=htmlpages&func=display&pid=1
See also these related projects.