Thanks Jason - that looks exactly what i need 
I think i can get this working with what i have at the moment - i just need to extract the xml tags which exists as variable already. Hopefully the code below will make sense in what i am trying to do (if its possible!).
Code:
<?php
$xmlresult = "<book>
<title>My Book</title>
<chapter id="1">
<title>Chapter 1</title>
<para>Donec velit. Nullam eget tellus vitae tortor gravida scelerisque.
In orci lorem, cursus imperdiet, ultricies non, hendrerit et, orci.
Nulla facilisi. Nullam velit nisl, laoreet id, condimentum ut,
ultricies id, mauris.</para>
</chapter>
<chapter id="2">
<title>Chapter 2</title>
<para>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Proin
gravida. Phasellus tincidunt massa vel urna. Proin adipiscing quam
vitae odio. Sed dictum. Ut tincidunt lorem ac lorem. Duis eros
tellus, pharetra id, faucibus eu, dapibus dictum, odio.</para>
</chapter>
</book>"
$xml = <<<EOD;
$xml.= $xmlresult;
$xml.= EOD;
$simplexml = new SimpleXMLElement($xml);
$title = $simplexml->title;
$chapter1Title = $simplexml->chapter[0]->title;
$chapter2Para = $simplexml->chapter[1]->para;
echo $title . '<br />' . $chapter1Title . '<br /> ' . $chapter2Para;
?>
Cheers
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