RT, the Queen Mum was queen but not monarch, there's a clear difference. If the monarch's a king, he MAY make his wife queen, but she would not have any power as monarch. If the monarch's a queen, she will most likely make her husband prince (or even duke), as she's the monarch, and would not elevate her spouse above her. Diana would have been queen, but only as consort to the king, i.e, wife to the monarch, Charles, a position similar to the Queen Mum's. Camilla can never marry Charles, muchless become queen if Charles becomes king, because as king, Charles also becomes sworn head of the Church of England, which forbids remarriage after divorce. I believe he will either have to remain a bachelor king, or if he really wants to marry her, abdicate the throne in favor of William.
Then again, Charles may never become King, as Queen Elizabeth II, even in her seventies, shows no sign of slowing down, and if her mother's any indication, Charles might very well die waiting for the throne.