That's interesting. I was thinking that I could learn some JavaScript from it, all that neat drag & drop and item placement stuff. Turned out that it uses Yahoo UI library for all the essential stuff, leaving only the actual game engine for the creator.
http://developer.yahoo.com/yui/
The YUI library is available under BSD license. Most probably worth to check out (especially for a JS newbie like me).
I couldn't seem to play it on my iPhone. Anyone else on ios 4 have trouble? I need the click event it seems.