Byte order Mark (BOM, UTF-8, Header)

The Problem: If I edit a php file with Microsoft Notepad and save with UTF-8 encoding there is a problem with headers. example: <?php header("Content-type: text/xml"); echo "<somexml/>"; ?> PHP tells me, that the header is already set, because of the (invisible) BOM http://de.wikipedia.org/wiki/Byte_Order_Mark I teach php and 50% of my students have this problems if they use UTF-8 encoding (depends on editor). My Question: ------------ Is PHP UTF-8 ready? Is there an other reason to stick on iso-8859-1 or ascii beside the BOM? Is it a PHP bug, or is it a bug of the editor software? thanks Bernhard