Kinderbach was a fun little program that will allow you to see how much interest your kids may have in piano lessons. I am not positive how much you can learn without a actual teacher guiding you, but this program is fun and will teach your kids. The fundamentals learned with Kinderbach piano lessons will have to be learned no matter which way you approach piano.
The program was fun and engaging for both of my kids, but only kept the interest of my oldest. She had just turned 7 when we began the piano lessons. She was quick to go through many of the levels. I hate that our computer caused some problems at the time, because that led to some frustration. She has asked to do piano lessons for a while now. She loved the bright animation, the simple techniques, and the songs.
You can visit the Kinderbach website to enjoy a free sample lesson and check out all the options available to you. This may be an easy alternative to get your kids involved in music and see what their talents and desires are.