Here is a more direct link to those Montessori bells:
http://sourceforge.net/projects/mbells/files/mbells/mbells-1.1/mbells_1.1.jar/downloadI'm not an expert at all, but the bells sound like the Solfege to me - which I understand is a great way to start exposing kids to music.
The app. scrambles the sounds and asks you to pair and grade them so that they are in the Solfege order.
mom2ross