My son is also 6 (in private school Kindergarten) and is doing some higher math there. His teacher gives him 3rd grade worksheets that haven't, however, touched on multiplication.

Since he's shown interest, at home he's learning multiplication using Disney's Schoolhouse Rock-Multiplication. They have a great interactive DVD you can find on Amazon.

It makes me smile to hear my son sing the songs to get the answers to quizzes I give.