If you haven't heard about it, here's a great app family that is a really fun way to practice music...
http://www.joytunes.com
Joytunes offers piano apps for iPad, which can be used with a piano (the microphone hears the sounds and gives feedback and assessment and turns piano practice into a fun game!
http://parents.joytunes.com gives a good introduction into the piano maestro app.
Also, 4th grade students at Miller have been using http://www.joytunes.com/express to learn recorder note-reading and http://www.joytunes.com/master in a fun game involving using your recorder as a video game controller. (correct notes equal points earned). These websites are FREE and work with any computer that has a microphone (they work best when the student wears headphones to hear the music.)
Give these a try! If you have a fourth grader, ask them to show you what they can do using Joytunes!