InstantMessengers with Jabber support:

• GTK/GNOME

  • Gaim, a multiprotocol GTK2 InstantMessenger which has a Jabber plugin
  • Gossip, another GTK2 Jabber client.
  • gnome-jabber - but development of this has halted, and merged efforts with the gossip team.
  • Gabber for GNOME (uses GTK)
  • Gabber2, the GTK2 port of Gabber. Their website says that development has paused unless/until someone steps forward to lead the project (Oct 2004).

• Qt/KDE

  • Psi, the canonical Qt client (also runs on MacOSX and MicrosoftWindows)
  • Kopete, KDE's main multiprotocol IM client.
  • Konverse for KDE. Webpage was last updated in 2001.

• Console

  • CenterIcq, a multiprotocol Curses InstantMessenger which has a Jabber plugin
  • imcom, requires Python
  • jabmsg batch-mode Jabber message sender, requires Perl

• MacOSX

  • Adium X, based on libgaim. GPLed.
  • Nitro
  • Fire, has a crappy icon.

• MicrosoftWindows

  • Exodus
  • Jabber.com's client. Current version seems to only let you connect to Jabber.com's server
  • JAJC
  • Pandion, MSN Messenger for Jabber. Looks really nice in Windows XP. Previously known as RhymBox.
  • Neos MT Win32 Jabber client that supports digital whiteboard, audio & video over IP, and file transfer with history.

• Others

  • Tkabber, written in TclTk (requires a couple of extra TCL libraries) so this should run on any OperatingSystem that TclTk runs on. Its UserInterface sucks, but it's very feature complete.
  • The Coccinella, also written in TclTk, and also has a sucky UserInterface. However, it boasts a shared whiteboard where you can do some cooperative drawing with other Coccinella users, and good support for the multiuser room administration options.
  • Greenthumb — a Java applet