In a large skillet brown the chicken in butter/margarine. Season with salt and pepper. Remove from skillet and place in a lightly greased 9x13 inch baking dish.
In the drippings (in the skillet), saute onion and celery until tender. Add cranberry sauce and barbecue sauce. Mix well.
Pour cranberry mixture over chicken and bake in the preheated oven for 90 minutes, basting every 15 minutes.