function rockable_googlemap($atts, $content = null) {
   extract(shortcode_atts(array(
               "width" => '940',
               "height" => '300',
               "src" => ''
   ), $atts));

return '<div>
            <iframe src="'.$src.'&output=embed" frameborder="0" marginwidth="0"
marginheight="0" scrolling="no" width="'.$width.'" height="'.$height.'"></iframe>
        </div>
        ';
}

add_shortcode("googlemap", "rockable_googlemap");