I doubt anyone here is going to code one up for you, in which case, you're expecting someone to write up a tutorial? In which case, lazy.

Simply insert the below code to the END of your document, right above the </BODY> tag.
<script>
if (!document.layers)
document.write('<div id="divStayTopLeft" style="position:absolute">')
</script>
<layer id="divStayTopLeft">
<!--EDIT BELOW CODE TO YOUR OWN MENU-->
<table border="1" width="130" cellspacing="0" cellpadding="0">
  <tr>
    <td width="100%" bgcolor="#FFFFCC">
      <p align="center"><b><font size="4">Menu</font></b></td>
  </tr>
  <tr>
    <td width="100%" bgcolor="#FFFFFF">
      <p align="left"> <a href="http://www.dynamicdrive.com">Dynamic Drive</a><br>
       <a href="http://www.dynamicdrive.com/new.htm">What's New</a><br>
       <a href="http://www.dynamicdrive.com/hot.htm">What's Hot</a><br>
       <a href="http://www.dynamicdrive.com/faqs.htm">FAQs</a><br>
       <a href="http://www.dynamicdrive.com/morezone/">More Zone</a></td>
  </tr>
</table>
<!--END OF EDIT-->
</layer>
<script type="text/javascript">
/*
Floating Menu script-  Roy Whittle (http://www.javascript-fx.com/)
Script featured on/available at http://www.dynamicdrive.com/
This notice must stay intact for use
*/
//Enter "frombottom" or "fromtop"
var verticalpos="frombottom"
if (!document.layers)
document.write('</div>')
function JSFX_FloatTopDiv()
{
	var startX = 3,
	startY = 150;
	var ns = (navigator.appName.indexOf("Netscape") != -1);
	var d = document;
	function ml(id)
	{
		var el=d.getElementById?d.getElementById(id):d.all?d.all[id]:d.layers[id];
		if(d.layers)el.style=el;
		el.sP=function(x,y){this.style.left=x;this.style.top=y;};
		el.x = startX;
		if (verticalpos=="fromtop")
		el.y = startY;
		else{
		el.y = ns ? pageYOffset + innerHeight : document.body.scrollTop + document.body.clientHeight;
		el.y -= startY;
		}
		return el;
	}
	window.stayTopLeft=function()
	{
		if (verticalpos=="fromtop"){
		var pY = ns ? pageYOffset : document.body.scrollTop;
		ftlObj.y += (pY + startY - ftlObj.y)/8;
		}
		else{
		var pY = ns ? pageYOffset + innerHeight : document.body.scrollTop + document.body.clientHeight;
		ftlObj.y += (pY - startY - ftlObj.y)/8;
		}
		ftlObj.sP(ftlObj.x, ftlObj.y);
		setTimeout("stayTopLeft()", 10);
	}
	ftlObj = ml("divStayTopLeft");
	stayTopLeft();
}
JSFX_FloatTopDiv();
</script>
	It doesn't work.

<HTML>
<BODY>
<p>Of course it works :)</p>
<br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>
<br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>
<br><br><br>
<script>
if (!document.layers)
document.write('<div id="divStayTopLeft" style="position:absolute">')
</script>
<layer id="divStayTopLeft">
<!--EDIT BELOW CODE TO YOUR OWN MENU-->
<table border="1" width="130" cellspacing="0" cellpadding="0">
  <tr>
    <td width="100%" bgcolor="#FFFFCC">
      <p align="center"><b><font size="4">Menu</font></b></td>
  </tr>
  <tr>
    <td width="100%" bgcolor="#FFFFFF">
      <p align="left"> <a href="http://www.dynamicdrive.com">Dynamic Drive</a><br>
       <a href="http://www.dynamicdrive.com/new.htm">What's New</a><br>
       <a href="http://www.dynamicdrive.com/hot.htm">What's Hot</a><br>
       <a href="http://www.dynamicdrive.com/faqs.htm">FAQs</a><br>
       <a href="http://www.dynamicdrive.com/morezone/">More Zone</a></td>
  </tr>
</table>
<!--END OF EDIT-->
</layer>
<script type="text/javascript">
/*
Floating Menu script-  Roy Whittle (http://www.javascript-fx.com/)
Script featured on/available at http://www.dynamicdrive.com/
This notice must stay intact for use
*/
//Enter "frombottom" or "fromtop"
var verticalpos="frombottom"
if (!document.layers)
document.write('</div>')
function JSFX_FloatTopDiv()
{
	var startX = 3,
	startY = 150;
	var ns = (navigator.appName.indexOf("Netscape") != -1);
	var d = document;
	function ml(id)
	{
		var el=d.getElementById?d.getElementById(id):d.all?d.all[id]:d.layers[id];
		if(d.layers)el.style=el;
		el.sP=function(x,y){this.style.left=x;this.style.top=y;};
		el.x = startX;
		if (verticalpos=="fromtop")
		el.y = startY;
		else{
		el.y = ns ? pageYOffset + innerHeight : document.body.scrollTop + document.body.clientHeight;
		el.y -= startY;
		}
		return el;
	}
	window.stayTopLeft=function()
	{
		if (verticalpos=="fromtop"){
		var pY = ns ? pageYOffset : document.body.scrollTop;
		ftlObj.y += (pY + startY - ftlObj.y)/8;
		}
		else{
		var pY = ns ? pageYOffset + innerHeight : document.body.scrollTop + document.body.clientHeight;
		ftlObj.y += (pY - startY - ftlObj.y)/8;
		}
		ftlObj.sP(ftlObj.x, ftlObj.y);
		setTimeout("stayTopLeft()", 10);
	}
	ftlObj = ml("divStayTopLeft");
	stayTopLeft();
}
JSFX_FloatTopDiv();
</script>
</BODY>
</HTML>
	It doesn't work.