It has been released.... For pc Only....
Well, I'm guessing at least it'll be Mac compatible once it's past Beta.
(edit : my primary motivation to buying all Sim games is the creativity/building factors and I was certain that we'd be able to create our own towns and terrains etc... - if this isn't released for the Mac at all I'll be dropping this game altogether)
Signed... Looking forward to the mac I'm getting for christmas, but I've just gotten used to and starting to enjoy this tool