Display notice for products of specific categories in cart?

I want some help with mage开发者_如何学运维nto! All i want to do is to display a note or a warning (regarding shipping or a simple note) under the condition that if the cart contains any product lets say from category 4 or 6 or 8 etc..

Any help would be appreciated! Thanks.

Regards.

$cart = Mage::getModel('checkout/cart');
$quote = $cart->getQuote();
foreach($quote->getAllItems() as $item){
    $product = Mage::getModel('catalog/product')->load($item->getProductId());
    foreach($product->getCategoryIds() as $cat_id){
        if($cat_id == 6||...) {
           ... do your stuff
        }
    }
}

Hope that helps