Still not showing here at my work, on IE8 - I did some research, see this thread:
Several things in there to try - I would first try on the link where you have:
<link rel="shortcut icon" type="image/x-icon" href="http://arduino.cc/favicon.png">
...in the HTML - changing it to:
<link rel="shortcut icon" type="image/x-icon" href="http://www.arduino.cc/favicon.png">
Perhaps you could do that to the second link, or remove it entirely...?
