When I've added this code no setting on width and height works
jQuery(document).ready(function() {
$('a.iframe').fancybox();
});
What are the options to get around it?
Take a look at the documentation here: http://fancybox.net/api
You're using inline content, so make sure that you're setting the autoDimensions option to false along with the width and height settings.
UPDATE: I tested the following solution successfully:
$('a.fbtag').fancybox({
autoDimensions: false,
height: 300,
width: 400
});
This assumes that the class name of the link you're opening is 'fbtag'.