The Portable Freeware Collection Forums

I would like to suggest an app called Portable Psi. It is a portable version of the Jabber client Psi. This will allow you to log into your GTalk account or any other Jabber account from anywhere!

http://www.portasoft.org/e107/page.php?17

You can also login to FaceBook Chat (which I do not have) due to it is XMPP, as well.
You'll need to create a FaceBook Username.

Instructions
Howto: Facebook Chat XMPP settings — Bay Area Tech Pros
Integrating Facebook Chat Everywhere

FaceBook Jabber/XMPP
Facebook Now Supports Jabber/XMPP - Slashdot
http://www.facebook.com/sitetour/chat.php

Warning! FaceBook is, in fact, a compromised and an insecure XMPP chat since it is not using SSL but why using Facebook when you can login to every domain that is connected to a server that has XMPP installed on?

If you insist on using FaceBook than consider to use a transport (see below) with the LibPurple plugin pidgin-facebookchat which has better security (SSL/TLS)).

Transports
You can also use Gateway/Transport Agents* which are actually, by most, the protocol resolvers of the LibPurple library which is being used by Adium and Pidgin.
The two main benefits are:

• Decentralized, it is not limited to the AOL network or the Yahoo! or the FaceBook networks etc... XMPP is iter-server inter-domain.
• Services like AIM, Facebook, GTalk, ICQ, Identi.ca, IRC, MSN, Twitter etc. will only see the IP address of the transport (no yours).

When the Egyptian ruling-class censored FaceBook and Twitter, those that uses Jabber/XMPP could post at Twitter and could Chat with FaceBook Chat!

Use only XMPP

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* Click here to see a screenshot of a Jabber/XMPP client software in action.

Very old thread update:

The Jabber Psi client was still active as of 2020: https://psi-im.org/ with portable versions listed on the download page: https://psi-im.org/download/

While Portasoft site (mentioned above) faded out back in 2006, here's an original site link that seems to work: https://web.archive.org/web/20060813202 ... age.php?17