I found this:
http://www.people.vcu.edu/~bhammel/theory/resources/flash/fixed%20do%20keyboard.swf
From my readings about teachers teaching younger kids music Solfege seems like the consensus of how to teach but perfect pitch is taught in conjunction.
Here is a discussion of the progression of teaching kids music :
http://www.menc.org/forums/viewtopic.php?id=2832
Here is another page with music teaching ideas :
http://munchkinsandmusic.blogspot.com/search/label/Music%20Lessons
Here is a good site on teaching intervals:
http://lalemantpolyphonic.org/INTERVAL/main_menu.htm
How are you using the Solfege keyboard?