This function will allow you to create XML document with simple PHP array variable. Nodes are just stacked onto each other and naming it 'Attribute_XXX' will add atribute XXX to that parent node.

function to_xml(SimpleXMLElement $object, array $data)
{
    $attr = "Attribute_";
    foreach ($data as value) {
        if (is_array($value)) {
            $new_object = $object->addChild($key);
            to_xml($new_object, $value);
        } else {
            if(strpos(attr) !== false){
                $object->addAttribute(substr($key, strlen($attr)), $value);
            }else{
                $object->addChild(value);
            }
        }
    }
}

Usage:

$my_array = array (
    'TagN1' => array (
        'TagInsideOfIt' => array (
            'Atrribute_IDuser' => 'anything',
            'RegularTag' => 'whatever',
            'Address' => array(
                'Attribute_ID' => '111',
                'Attribute_key' => 'aaa',
                'Company' => 'Google Inc.'
            )
        )
    )
);

$xml = new SimpleXMLElement('<root/>');

to_xml(my_array);

Header('Content-type: text/xml');
print($xml->asXML());

easy!

$xml = simplexml_load_string($xmlstring, "SimpleXMLElement", LIBXML_NOCDATA);
$json = json_encode(array = json_decode($json,TRUE);

Here is php 5.2 code which will convert array of any depth to xml document:

Array
(
    ['total_stud']=> 500
    [0] => Array
        (
            [student] => Array
                (
                    [id] => 1
                    [name] => abc
                    [address] => Array
                        (
                            [city]=>Pune
                            [zip]=>411006
                        )                       
                )
        )
    [1] => Array
        (
            [student] => Array
                (
                    [id] => 2
                    [name] => xyz
                    [address] => Array
                        (
                            [city]=>Mumbai
                            [zip]=>400906
                        )   
                )

        )
)

generated XML would be as:

<?xml version="1.0"?>
<student_info>
    <total_stud>500</total_stud>
    <student>
        <id>1</id>
        <name>abc</name>
        <address>
            <city>Pune</city>
            <zip>411006</zip>
        </address>
    </student>
    <student>
        <id>1</id>
        <name>abc</name>
        <address>
            <city>Mumbai</city>
            <zip>400906</zip>
        </address>
    </student>
</student_info>

PHP snippet

<?php
// function defination to convert array to xml
function array_to_xml( $data, &$xml_data ) {
    foreach( $data as $key => $value ) {
        if( is_array($value) ) {
            if( is_numeric($key) ){
                $key = 'item'.$key; //dealing with <0/>..<n/> issues
            }
            $subnode = $xml_data->addChild($key);
            array_to_xml($value, $subnode);
        } else {
            $xml_data->addChild("$key",htmlspecialchars("$value"));
        }
     }
}

// initializing or creating array
$data = array('total_stud' => 500);

// creating object of SimpleXMLElement
$xml_data = new SimpleXMLElement('<?xml version="1.0"?><data></data>');

// function call to convert array to xml
array_to_xml($data,$xml_data);

//saving generated xml file; 
$result = $xml_data->asXML('/file/path/name.xml');

?>

Documentation on SimpleXMLElement::asXML used in this snippet