How do I prepare my child for her new sibling?

My friend started to refer to her baby bump by name to her 3 year old son as soon as it was prominent. She'd refer to the bump as his little sister right from the start and would tell him that she was living inside her as he did once and will come to stay with the family in a couple of months. This created an awareness of his sister's existence even before she was physically there. When the baby was born, my friend and her husband presented their son with a gift saying that it was from his sister