The piano is a great instrument, but it's certainly not cheap to buy one. If you want to learn how the instrument works a more economical solution might be to install miniPiano on your Palm.
Granted, miniPiano is far removed from the real thing, but at least it gives you a flavor of where the notes are and how they sound. The software basically installs a keyboard display on your screen and you simply need to touch the keys to play music. A musical score displayed above the keyboard shows you which note you've played in musical notation form.
One of the great things about miniPiano is the fact that it can play back the notes you've entered, allowing you to actually compose music on your Palm. You can then save your MIDI music to share with your pals.
Unfortunately, I felt miniPiano could've been a little better designed. The fact that not all keys are displayed on screen at the same time (you need to use arrow buttons to scroll along the keyboard) makes it quite a cumbersome experience at times. Likewise, the musical notations at the top of the miniPiano interface need to be scrolled too. Also, the sound of the piano is quite tinny and not much like the real thing.
Nevertheless, miniPiano makes for a bit of fun for anyone interested in how a piano works.