ICQnix is a clone of ICQ intended to resemble the Mirabilis client as much as possible. It is placed under the GPL, with the exception that it may be linked to Qt. I will upload in a day or so if no one objects (I searched the archives and wnpp and didn't see anyone had dibs on this, but if I missed it, let me know).
URL: http://icqnix.linuxbox.com/