How can I add a facebook 'share' button

To set up face book share go to the 'header/footer' section and enter the following code in your interblog settings

<?php
global $urlToThisPage;  
$blogPostPermaLink="$urlToThisPage?id=".$myEntry['POSTID'];
$postid=$myEntry['POSTID'];
 $myTitle=$myEntry['TITLE'];
print "<a name='fb_share' type='button_count' share_url='$blogPostPermaLink' href='http://www.facebook.com/sharer.php?u=$blogPostPermaLink&t=$myTitle'>Share</a>";
?>

Set Interblog to 'insert after 0 posts and then ever 1 post' and check the evaluate PHP code button.

Then in the 'footer' section add the following code

  <script src="http://static.ak.fbcdn.net/connect.php/js/FB.Share" type="text/javascript"></script>

Make sure both of the above are set to 'ignore formatting' (pink) by selecting them and hitting cmd-.

Now you should be good to go!