Here are XMPP settings to connect to facebook chat with your favorite client. We recommend Pidgin, PSI, or Miranda IM.
Protocol: XMPP
Username: Your Facebook Vanity Name
Domain: chat.facebook.com
Jabber ID: vanityname@chat.facebook.com
Password: <Facebook password>
Connect port: 5222
Connect server: chat.facebook.com
Use SSL/TLS: no
Allow Plaintext Authentication: no
So if you are setting it up for Pidgin, your settings should look something like this:
If you are still having trouble, check out the official support page.
If you have a firewall blocking port 5222, you can also use 443.
Please Update Facebook Xmpp Settings
Changed settings are:
Connect port: 443
Use SSL/TLS: yes
Allow Plaintext Authentication: yes