Convert XML exchange rates from arionbanki.is to JSON or JSONP for money.js (http://josscrowcroft.github.io/money.js/)

exchange-rates.php

<?php

$xml_url = 'http://www.arionbanki.is/markadir/gjaldmidlar/gengi/xml-export';
$data = simplexml_load_file($xml_url);

$out = array(
    'timestamp' => time(),
    'base' => 'ISK',
    'rates' => array()
);

foreach($data->items->Currency as $cur) {
    if(isset($_GET['tegund']) and $_GET['tegund'] === 'kaup') {
        $gengi = (float)$cur->Kaupgengi;
    } else {
        $gengi = (float)$cur->Solugengi;
    }

    $mynt = (string)$cur->mynt;

    $out['rates'][$mynt] = $gengi;
}

$json = json_encode($out);

if(!empty($_GET['callback'])) {
    echo $_GET['callback'] . '(' . $json . ')';
} else {
    echo $json;
}