The goal of Gajim is to provide a full featured and easy to use Jabber client. Gajim works nicely with GNOME, but does not require it to run. It is released under the GNU General Public License.
Features: - Tabbed chat window
- Group chat support (with MUC protocol)
- Emoticons, Avatars, File transfer, Room Bookmarks
- Metacontacts Support
- Trayicon, Speller, extented chat history functionalities
- TLS and GPG support (with SSL legacy support)
- Transport Registration support
- Service Discovery including Nodes
- Wikipedia, dictionary and search engine lookup
- Multiple accounts support
- DBus Capabilities. Read more information
- XML Console
- Gajim is available in 22 languages: Basque, Belarusian, Brasilian, Breton, Bulgarian, Chinese (simplified), Croatian, Czech, Dutch, English, Esperanto, French, German, Greek, Italian, Norwegian (Bokmål), Polish, Portugese, Russian, Spanish, Slovak and Swedish
Gajim Screenshot:

Technorati Tags: im, messenger, instant messaging, instant messenger, Jabber, Gajim
What I like about Gajim is that it has the sleek user interface of Gaim, but keeps it simple and focuses on being a pure Jabber/XMPP client.
However the Norwegian localisation of Gajim is terrible. And there is a really annoying bug that allows you to have to instances, causing you to sign on and off the server until your banned.