sxe.php

<?php

$xml_source = <<<EOF
<BackupSets>
    <BackupSet ID="1267529212700" >
            <BackupJob ID="2010-03-02-12-27-18" />
            <BackupJob ID="2010-03-02-12-29-00" />
            <BackupJob ID="2010-03-11-16-08-40" />
            <BackupJob ID="2010-03-18-16-03-59" />
            <BackupJob ID="2010-03-25-10-40-47" />
            <BackupJob ID="2010-04-08-16-34-08" />
            <BackupJob ID="2011-02-24-18-26-55" />
    </BackupSet>'
    <BackupSet ID="1298568455609" >
            <BackupJob ID="2011-02-24-18-28-21" />
    </BackupSet>
</BackupSets>
EOF;

$sxe = new SimpleXMLElement($xml_source);

foreach($sxe as $BackupSet) {

        echo "\nBackup Set ID: {$BackupSet['ID']}\n";

        foreach($BackupSet->BackupJob as $BackupJob) {
            echo ' - Backup Job ID: '.$BackupJob['ID']."\n";
        }

        echo "\n";

}