Então vamos lá :)

Primeiramente abra o painel do blogger,  clique em Design, Editar HTML

agora aperte CTRL+F e procure pela linha

Após encontrar a linha, cole o seguinte código imediatamente acima dela:

 #gb {
position:fixed;
top:150px;
z-index:+1000;
left:-610px;
}


* html #gb {
position:relative;
}


.gbtab {
height:161px;
width:47px;
float:right;
cursor:pointer;
background:url('http://picturestack.com/751/278/ouEHWwgKcpia53N.png') no-repeat;
margin-top:20px;
}


.gbcontent {
float:left;
border:2px solid #8c00c1;
background:#fff;
opacity:0.80;
-moz-opacity: 0.80;
filter: alpha(opacity=80);
-webkit-border-radius: 20px;
border-radius: 20px;
-khtml-border-radius: 20px;
padding:8px;
}


Agora procure por:


</body>


Cole o seguinte código imediatamente acima:


<script type='text/javascript'>
function showHideGB(){
var gb = document.getElementById(&quot;gb&quot;);
var w = gb.offsetWidth;
gb.opened ? moveGB(0, 47-w) : moveGB(20-w, 0);
gb.opened = !gb.opened;
}
function moveGB(x0, xf){
var gb = document.getElementById(&quot;gb&quot;);
var dx = Math.abs(x0-xf) &gt; 10 ? 5 : 1;
var dir = xf&gt;x0 ? 1 : -1;
var x = x0 + dx * dir;
gb.style.left = x.toString() + &quot;px&quot;;
if(x0!=xf){setTimeout(&quot;moveGB(&quot;+x+&quot;, &quot;+xf+&quot;)&quot;, 10);}
}
</script>


<div id='gb'>
<div class='gbtab' onclick='showHideGB()'> </div>
<div class='gbcontent'>
<div style='line-height:0;background-position:center;width:590px;height:310px;'>


<embed align='middle' allowscriptaccess='sameDomain' flashvars='id=165223483' height='310' name='chat' pluginspage='http://xat.com/update_flash.shtml' quality='high' src='http://www.xatech.com/web_gear/chat/chat.swf' type='application/x-shockwave-flash' width='590' wmode='transparent'/>


</div>
</div>
</div>