On occasion, I have doled out punishment to my son for lying. In particular, he did something wrong and when questioned about this, lied and said he did not do it. Depending on what he did wrong in the first place, he might receive X days of punishment. However, if he lied, he will have 2X more days tacked on.
On at least one occasion, what I considered a punishable offense was reduced when he came to me and 'fessed up before I found out.
I know that my son will not stop incorrect behavior altogether at his age. However, I try to instill in him the lesson that no matter what you did