Rinse chicken and pat dry. Season with salt and pepper to taste. Coat with mustard.
Pour half of beer out of can and refill with Italian style dressing. Place can on a disposable baking tray. Set chicken upright on beer can (it acts as a stand), inserting can into cavity of the chicken.
Place baking tray with beer and chicken on the preheated barbecue. Cover and cook about 1 hour until chicken is no longer pink and juices run clear.