Edit in JSFiddle

$('a[href^="http://"]').filter(function() {
    return this.hostname && this.hostname !== location.hostname;
}).each(function(){
    var l = $(this);
    var fu =
    l.attr('href').replace(/^(http:\/\/[^\/]+).*$/, '$1') + '/favicon.ico';
    var fi = $('<img src="favicon.png" alt="favicon" />')['prependTo'](l);
    var e = new Image();
    e.src = fu;
    if (e.complete) fi.attr('src', fu);
    else e.onload = function(){
        fi.attr('src', fu);
    };
});

a { display: block; text-decoration: none; padding: 5px; }

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<a href=http://jsfiddle.net/chriscoyier/6Vg7t/3/>JSfiddle</a>
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