<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.5/jquery.min.js"></script>
<script>
function facebook() {
$("#facebook").fadeIn();
$("#boton").fadeOut();
}
function boton() {
$("#boton").fadeIn();
$("#facebook").fadeOut();
}
</script>
<body style="background: black;">
<div id="boton" class="boton" style="width:33px; height:120px; position:fixed; right:0px; bottom:200px;" onMouseOver="facebook()">
<img src="http://u.jimdo.com/www38/o/sa1c23512e426e90b/img/i36114fd42df15eb0/1340077369/std/image.png" onMouseOver="facebook()" alt="" />
</div>
<div id="facebook" class="facebook" style="background:#FFF; width:450px; height:450px; position:fixed; display:none; right:0px; bottom:200px;" onMouseOut="boton()">
<iframe src="http://www.facebook.com/plugins/live_stream_box.php?app_id=AQUI EL ID DE TU APLIACION&width=450&height=450&via_url&always_post_to_friends=true" scrolling="no" frameborder="0" style="border:none; overflow:hidden; width:450px; height:450px;"></iframe>
</div>
</body>