Hide “Update” item on wordpress admin menu

I’m trying to hide this item in the admin:

http://webkunst.comeze.com/1.png

I have already removed the updated message using this:

add_action('admin_menu','wphidenag');
    function wphidenag() {
remove_action( 'admin_notices', 'update_nag', 3 );
}

But I haven’t found a solution to this item, any ideas to do it the proper way, not with css?

I tried this solution but it only stops the plugins from being updated, it still shows the menu item if the plugin doesn’t have any update:
http://developersmind.com/2010/06/12/preventing-wordpress-from-checking-for-updates-for-a-plugin/?replytocom=81