var xml = '<?xml version="1.0"?><methodCall>' +
    '<methodName>system.methodSignature</methodName>' +
    '<params>' +
    '<param><value><string>node.load</string></value></param>' +
    '</params></methodCall>';

alert(xml); // this prints out the xml as it looks
alert( $('div', xml).text()); // this returns your page filtered for 'div'