Edit in JSFiddle

Result
JavaScript
CSS
HTML

$("a[href^='http']").each(function() {
    $(this).css({
        background: "url(http://favicon.hatena.ne.jp/?url=" + this.href + ") left center no-repeat"
    });
});

a { display: block; text-decoration: none; padding: 5px 5px 5px 20px; }

<a href=http://github.com>GitHub</a>
<a href=http://css-tricks.com>CSS-Tricks</a>
<a href=http://www.google.com>Google</a>
<a href=http://jsfiddle.net/chriscoyier/6Vg7t/3/>JSfiddle</a>
<a href=http://kachibito.net/>kachibito</a>