I'm assuming you are talking about the Paladin's Smite Evil, with is a Supernatural ability, which requires a Standard action, thus you cannot use it on a charge.
As it is a standard action to smite, you cannot use it on a Cleave attack.
The damage on the cleave would not be doubled. "The first charge attack you make before the end of the round deals double damage on a successful hit." Your cleave attack would not be the "first charge attack," and as such would not be doubled.