jQuery.parseXML()

var xml = '<rss version="2.0"><channel><title>RSS Title</title></channel></rss>',
    xmlDoc = $.parseXML( xml ),
    $xml = $( xmlDoc ),
    $title = $xml.find( 'title' );	    

// append "RSS Title" to #someElement
$( '#someElement' ).append( $title.text() );	

// change the title to "XML Title"
$title.text( 'XML Title' );

// append "XML Title" to #anotherElement
$( '#anotherElement' ).append( $title.text() );