This is standard facebook recomend-botton:
<div id="fb-root"></div>
<script>(function(d, s, id) {
var js, fjs = d.getElementsByTagName(s)[0];
if (d.getElementById(id)) return;
js = d.createElement(s); js.id = id;
js.src = "//connect.facebook.net/en_US/all.js#xfbml=1";
fjs.parentNode.insertBefore(js, fjs);
}(document, 'script', 'facebook-jssdk'));
</script>
And place this html where you want your button:
<div class="fb-like" data-href="http://www.myshop.com/products/123" data-send="false" data-width="450" data-show-faces="false" data-action="recommend"></div>
The onlye thing you should change on every productpage is fex the product-id. As you can see the div-tag (at bottom) contains an attribute "data-href" (permanent link to each product). This is the unique url to "like" when you hit the like-button.
http://developers.facebook.com/docs/reference/plugins/like/[
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