Thanks Jason.
I have tried to do this, but it seems to be picking up the page title.
Does this look right?
<a name="fb_share" type="icon" href="#" onclick="window.open('http://www.facebook.com/sharer.php?u=<?php echo urlencode(((!empty($_SERVER["HTTPS"])) ? "https://" : "http://") . $_SERVER["SERVER_NAME"].$_SERVER["REQUEST_URI"]); ?>&t=Set%20of%203%20Christmas%20Decoration', 'Facebook', 'toolbar=0,status=0,width=626,height=436'); return false;" title="Facebook">