My grandson likes playing 'Guess what song it is'

My grandson likes music a lot. We allways play and sung different types of song throught the world. He likes a lot playing to guess what music he is singing. he goes 1,2,3 notes and we have to guess the song. I am surprised how well he follows the song. I am afraid we are wasting a good musician by not starting piano lessons. But for now my son is more worried in his pronunciation.

Do you know any free web sites that may be use to teach piano to a kid ?