vqcc-gtk is a chat application written in C for the GTK+ toolkit, primarily
used in small LAN's. It is based on quickChat/Vypress Chat (TM) for Windows
(from Vypress Research) and is licensed under the GPL.

The application supports both quickChat and Vypress Chat(TM) protocols and
hopefully is compatible enough to substitute those applications when using
Linux, FreeBSD or another *NIX desktop. You need no server to run, however
it is not possible to communicate outside your LAN (or subnet).

(From the About page)

WWW: http://vqcc-gtk.sourceforge.net/