var myEffect;

function scroll(){
    var speed = 20;
    var dur = ($('news_scrollpane').getHeight() + $('news_scrollpane').positionedOffset()[1]) / speed;
    myEffect = new Effect.Move('news_scrollpane', {
        x: 0,
        y: $('news_scrollpane').getHeight() * -1,
        mode: 'absolute',
        duration: dur,
        transition: Effect.Transitions.linear,
        afterFinish: function () {
            $('news_scrollpane').setStyle({
                top: $('news_frame').getHeight() + 'px'
                });
            scroll();
        }
    });
}

function stop() {
    myEffect.cancel();
}

document.observe("dom:loaded", function() {
    $('news_scrollpane').setStyle({
        top: $('news_frame').getHeight() + 'px'
    });
}); 

Event.observe(window, 'load', function () {
    scroll();
});