MessengeRoo

Now, Facebook Chat can be connected to any XMPP ( Jabber ) Client (Extensible Messaging and Presence Protocol) directly from your desktop computer. This means that iChat(Mac) can be used to make a chat using your Facebook Chat Account. Here are the sort tutorial you can follow:

1. Go to the iChat menu and select “Preferences.”

   

2. Click “Accounts,” then click the “+” at the bottom.
3. Select “Jabber” from the pull-down menu, then enter the following info:
   Screen Name: youfacebookusername@chat.facebook.com
   Password:your Facebook password
4. Click the arrow next to “Server Options” and enter the following info:
   Server: chat.facebook.com
   Port: 5222
   (Uncheck the box labeled “Use SSL”)

Youtube Video How to setup Facebook Chat in iChat

Beside iChat you can also use others XMPP Jabber Client such as Adium, Miranda, Pidgin or else.

Source: Facebook