I have successfuly managed to login to facebook via xmpp protocol.
I used PHP code provided in facebook\'s documentation found here:
Send <presence /> to go online.
The server will then send you several <presence from='friend1@chat.facebook.com/deviceID' /> indicating online friends.
Send a message like this:
<message from='juliet@example.com' to='romeo@example.net'>
<body>Art thou not Romeo, and a Montague?</body>
</message>