If your child isn't ready to hear the truth, they simply won't accept it -- or if they're very young, they may truly not even comprehend what you are saying.
Tell your child that the rituals associated with Santa are just one way of expressing the joy of giving and your love for them. If you have younger kids, let the older ones be responsible for stuffing stockings and being Santa's helper.
When children start putting together in their minds that Santa Claus may not be real, they'll ask questions -- and that's an opening for parents to get them talking about what's logical or not to them.
Our daughter wanted to talk about some of the topics that the books brought up, such as menstruation and breast development. She recognized on her own that her body was changing before her friends', and that naturally led to discussions about how she felt about that.