First off under most any flavors of Windows XP this is relatively EASY!  If you encounter any differences under your version.  Let me know I’ll modify the steps.  I run Windows XP Pro on the box I wrote this on.

Step 1: Write some code.  Below is what I USED.

<html>
<header>
<title>Weather Background</title>
<script type=”text/javascript”>
seconds=300;
function start()
{
   window.setInterval(“countdown()”,1000);
}
function countdown()
{
   seconds–;
   var count = document.getElementById(“count”);
   count.innerHTML = seconds;
   if (seconds == 0)
   {
      window.location.href = “Test.html”;
   }
}
</script>
</header>
<body onload=”start()”; scroll=”no” bgcolor=”black” style=”overflow:hidden; height:90%;color:white”>
<div id=”bg_image” style=”position:absolute; top:30px; left:0px; height:100%; width:100%”>
<img alt”” id=”imgPhoto” style=”WIDTH: 100%; HEIGHT: 100%” src=”http://sirocco.accuweather.com/sat_mosaic_640x480_public/rs/isrsc.jpg” />
</div>
<center>Weather Reload in <div style=”display:inline;color:white” id=”count”><script type=”text/javascript”>document.write(seconds)</script></div></center>
</body>
</html>

Step 2: Save it in a file named Test.html or really anything you want.  Just make sure to alter the reference to the name of the .html file on line 16 in the code to the same filename.

Step 3: Point your .html code at the website you want to view for updates located on line 24.  Just change the http:// address there to the website you want.

Step 4: Change the amount of time you want this to update.  You don’t wanna poll their site so much you get IP Banned.  With the NWS I chose 300 seconds.

Step 5: Save your file in a location you’ll be able to find it.  I dropped mine on the Desktop and just left it there.

Step 6: Right click on your Desktop and pull up Display Properties.

Step 7: Left Click on Desktop Tab, and click on Browse.   This will open a window and you can browse for your .html file.

Step 8: Find and select it.  Click Open.  This will then make your .html the new backgound.

Step 9 – Final Step: Click Apply and close the Display properties box.  You done enjoy your background.

Note you may need to play with the Image size some of your background, again this is done in the same way you would for building a WEBsite.  Just tweak the code on lines 22-24 to fit your desired image.