If you fancy yourself as the next Elton John or Mozart then learning can be a costly experience. If you can't afford the expensive instruments themselves then perhaps you could try installing Smart Piano on your Windows Mobile Smartphone.
This free simple application allows you to play the piano simply by hitting the keys on your phone. Each button on your handset represents a different musical note, and these are outlined in the program's help section. As soon as you strike one of the buttons the note will play and it's position on the scale and on the piano keyboard will show on the graphical display.
Besides using the phone button to play notes, Smart Piano also includes four different chords (C Major, G Major, F Major and Middle C). These can be accessed using the directional buttons, and again the finger position will be shown in the main window.
Smart Piano proves to be very simple to use but likewise, it's also very simple in terms of its scope. For instance, there's only one piano octave available, and you can't create your own chords, so you're limited in terms of your creative scope.
As a simple tool for learning the piano though, Smart Piano is a fun little free app.