Heres a great beginner piano site for children. In fact its a general music site for kids with free learning activities and games. There is an amusing musical sketch pad which will convert your sketches into avant guard sounding music and then there are rhythm and melody games. This is great basic training for kids and being in the form of games makes it all the more acceptable to them.
Many of you have contacted me asking for some beginner piano chord charts. It seems that a lot of people want to play from music by reading the chord symbols. I will be producing a list of all the chords and publishing it here within a few weeks. Once you have learned the basic chords, you need to put some sort of rhythm to them, learn some inversions and you are well on your way to playing most popular songs.