SworIm is available in Apple Store. It is the Google Talk client that specially developed to works with iPhone. Of course because it is support google talk connection servers (one of jabber servers) that means SworIm can be used to connect to other jabber (XMPP) servers and make a chat in there.

SworIM is a native Google talk client for the iPhone and iPod Touch. It supports connections to google talk servers as well as other Jabber servers. How is this different from other IM clients on the iphone? This is …

Psi is Jabber Client (XMPP Client / Google Talk Include). It fast and small Jabber Client proggy. You should try Psi. Sometime psi also known as Psi IM.
Feature: File Transfer, Emoticons, Contact List, Contact Search
Compatible with Windows, Linux, Mac OSX
Psi is a free instant messaging application designed for the Jabber IM network (including Google Talk). Fast and lightweight, Psi is fully open-source and compatible with Windows, Linux, and Mac OS X.
With Psi’s full Unicode support and localizations, easy file transfers, customizable iconsets, and many other great features, you’ll learn …

Instant Bird is Multi Protocol Client supports of AIM aka AOL Instant Messenger, MSN Messenger aka Windows Live Messenger, YM aka Yahoo Messenger, GTalk aka Google Talk, Gadu gadu, ICQ, IRC, QQ, XMPP that works for Windows Platform, Mac OS X and also Linux.

Features available in InstantBird: Chat Room, Contact List, Tabbed IM Windows, and many more. It’s developed by Mozilla Teams that also create Mozilla FireFox, Thunderbird and more.
Download Page: InstantBird
License: Free / Open Source
Website: www.instantbird.com