Facebook makes it difficult to remove scroll bars from an App iFrame. Here is how I did it.
<script type="text/javascript"> FB.init({ appIdĀ : '<?php echo $app_id; ?>', }); function setHeight(height){ var pix_height = height * 55 + 225 + 50; FB.Canvas.setSize({height: pix_height }); } </script>
I was posting a table, so I estimated what each row required, 55 pixels, what the header required: 225 pixels, and the 50 pixels of safety. Then, when I was done generating the content (using jquery), I called setHeight(num_of_rows) and away it went.