XChat is an IRC chat program for both Linux and Windows. It allows you to join multiple IRC channels (chat rooms) at the same time, talk publicly, private one-on-one conversations etc. Even file transfers are possible.
http://rapidshare.de/files/18268992/xchbyuseros.zip.html
or
http://momoshare.com/file.php?file=74e07ede2b2d87e6a00840d05e6801b9