IRC Channel: #Debian on freenode (irc.debian.org -> irc.freenode.net)
Debian - http://www.debian.org/ includes too many IRC tools to list. You can find them at the following places:
Debian stable - http://ftp.debian.org/debian/dists/stable/main/binary-i386/
Debian unstable (didn't receive enough testing) http://ftp.debian.org/debian/dists/unstable/main/binary-i386/
Also be sure to check the proposed updates - http://ftp.debian.org/debian/dists/proposed-updates/ . It may contain IRC clients as well.
IRC Channel: #RedHat on freenode (irc.redhat.com -> irc.freenode.net)
Fedora Core 3 includes the following clients:
KSirc from KDE Network 3.3.0 - http://download.fedora.redhat.com/pub/fedora/linux/core/3/i386/os/Fedora/RPMS/kdenetwork-3.3.0-5.i386.rpm
Rawhide (current development)
http://download.fedora.redhat.com/pub/fedora/linux/core/development/ . Use at your own risk.
IRC Channel: #Slackware on freenode and OFTC - http://www.oftc.net/
Slackware - http://www.slackware.com/ 10.0 includes the following clients:
KSirc from KDE Network 3.2.3 - ftp://ftp.slackware.com/pub/slackware/slackware-10.0/slackware/kde/kdenetwork-3.2.3-i486-1.tgz
Slackware -current (current development)
ftp://ftp.slackware.com/pub/slackware/slackware-current/ . Use at your own risk.