eTunes

eTunes (i.e., easyTunes) allows even to those who are not professional musicians to create and play their own tunes.

In fact it is enough to click the piano-keys and eTunes will take care to code your inputs for the right output.
Files created by eTunes can be converted into audio-files (MP3) to be played by other audio applications (ex. iTunes), or may be used as RingTones for cellphones supporting the RTTTL format.
Beside a Tutorial (cfr. Help Menu), the Archive (Archive Menu) contains a good variety of samples, from very easy to pretty elaborate tunes.