class.php

<?php

/**
 *
 * Array 2 XML class
 * Convert an array or multi-dimentional array to XML
 *
 * @author Kevin Waterson
 * @copyright 2009 PHPRO.ORG
 *
 */
class array2xml extends DomDocument
{

    public $nodeName;

    private $xpath;

    private $root;

    private $node_name;


    /**
    * Constructor, duh
    *
    * Set up the DOM environment
    *
    * @param    string    $root        The name of the root node
    * @param    string    $nod_name    The name numeric keys are called
    *
    */
    public function __construct($root='root', $node_name='node')
    {
        parent::__construct();

        /*** set the encoding ***/
        $this->encoding = "ISO-8859-1";

        /*** format the output ***/
        $this->formatOutput = true;

        /*** set the node names ***/
        $this->node_name = $node_name;

        /*** create the root element ***/
        $this->root = $this->appendChild($this->createElement( $root ));

        $this->xpath = new DomXPath($this);
    }

    /*
    * creates the XML representation of the array
    *
    * @access    public
    * @param    array    $arr    The array to convert
    * @aparam    string    $node    The name given to child nodes when recursing
    *
    */
    public function createNode( $arr, $node = null)
    {
        if (is_null($node))
        {
            $node = $this->root;
        }
        foreach($arr as $element => $value) 
        {
            $element = is_numeric( $element ) ? $this->node_name : $element;

            $child = $this->createElement($element, (is_array($value) ? null : $value));
            $node->appendChild($child);

            if (is_array($value))
            {
                self::createNode($value, $child);
            }
        }
    }
    /*
    * Return the generated XML as a string
    *
    * @access    public
    * @return    string
    *
    */
    public function __toString()
    {
        return $this->saveXML();
    }

    /*
    * array2xml::query() - perform an XPath query on the XML representation of the array
    * @param str $query - query to perform
    * @return mixed
    */
    public function query($query)
    {
        return $this->xpath->evaluate($query);
    }

} // end of class

?>

result.xml

<?xml version="1.0" encoding="ISO-8859-1"?>
 <my_node>
  <node><name>steve irwin</name><address><number>1</number><street>stingray</street></address><age>25</age></node>
  <node><name>kylie minogue</name><address><number>12</number><street>bunny</street></address><age>48</age></node>
  <node><name>rolf harris</name><address><number>88</number><street>didge</street></address><age>23</age></node>
  <node><name>ian dury</name><address><number>83</number><street>drury</street></address><age>83</age></node>
</my_node>

usage.php

$array = array(
        array(
            'name'=>'steve irwin',
            'address'=>
                array('number'=>1, 'street'=>'stingray'),
            'age'=>25),
        array(
                'name'=>'kylie minogue',
            'address'=>
                array('number'=>12, 'street'=>'bunny'),
            'age'=>48),
        array(
            'name'=>'rolf harris',
            'address'=>
                array('number'=>88, 'street'=>'didge'),
            'age'=>23),
        array(
            'name'=>'ian dury',
            'address'=>
                array('number'=>83, 'street'=>'drury'),
            'age'=>83)
    );

try 
{
    $xml = new array2xml('my_node');
    $xml->createNode( $array );
    echo $xml;
} 
catch (Exception $e) 
{
    echo $e->getMessage();
}

?>