Jabberzilla is a
Jabber client for
Mozilla. It is relatively small since it doesn't
implement the Jabber
protocol itself; it depends on
JabberXM, a collection of
XPCOM classes, to do that. As a
consequence, it is mostly just user interface code.
Since it is based on Mozilla's XPFE, written in XUL, CSS, and Javascript, it is very portable. Unfortunately, it is still rather buggy and is at a fairly early stage in development. It is nevertheless an encouraging project, and a good codebase if people suddenly develop an urgent need for a Jabber client in Mozilla.