<?xml-stylesheet type="text/xsl" href="yourFile.xsl" ?>.
Second of all, for a beginner tutorial, I wouldn't make it as complicated with attribute names and multiple templates. I mean <xsl:call-template />? That is definitely not for beginners.
Internet Explorer has the MSXML parser, Gecko-based browsers (Firefox/Mozilla/Flock) has a built-in XSLT parser and Safari/Konqueror can also read XSLT correctly too. You don't need PHP to parse XSLT, browsers can do it.