What do you tell your kids about Santa?

Santa Claus is always a hot topic this time of year.  It brings back memories of my childhood.  I lived with my father during the week and from a very young age I knew that Santa was not real.  I don't remember caring very much...I mean, I still got the presents...who cares where they come from?  Then I would go to my mom's house on the weekend and she INSISTED that Santa was real.  Even to this day she has not admitted to me otherwise!  But I was wise enough to recognize her handwriting on the "From Santa" tags on my gifts.  I just played along for her sake :)

I struggle with how/when to bring up the truth about Santa to my boys.  Up to this point when they have asked something about Santa, we reply "what do you think?" and have conveniently ignored giving a straight answer.  I know I will draw the line at lying because I want my boys to trust that what I tell them is true.  This year I saw a blog post on this topic that I really like.  You can view it here.  The writer shares my conviction about telling the truth, and suggests doing it by teaching about the real Saint Nicholas and how Santa Claus came to be.  It suggested a Veggie Tales movie on the topic, which I'm going to check out.  What about you...how/when did you share the truth about Santa Claus with your kids?  And how do you keep them from spilling the news to other children whose parents want to keep up the fantasy?  I'd love to hear your input!