Gajim is a jabber client written in PyGTK. The goal of Gajim's developers is to provide a full featured and easy to use xmpp client for the GTK+ users. Gajim does not require GNOME to run, even though it exists with it nicely.
It features tabbed chat windows, groupchat support (MUC), emoticons, URL grabber, systray icon, TLS and GPG support, transport registration, service discovery, multiple accounts, ...