willcowd on "admin_menu and capability"

Hi All

I'm having problems with a menu page. I have setup

add_action('admin_menu', 'todays_orders_page'); 

function todays_orders_page() {
	add_menu_page('Todays orders', 'Todays orders', 'todays_orders', __FILE__,'todays_orders');
}

However, visiting the page with a user who has "todays_orders" capability results in a permission denied error.

Any help would be great.

Thanks
Mark