It’s finally confirmed.  OS X 10.6 aka. Snow Leopard will only support Intel based Macs.  It had to happen at some point, but you can’t support multiple platforms forever.  Snow Leopard offers much in the way of multiprocessor/GPU/CPU support and will open the doors to very interesting functionality and developments for the future.  It’s by no means revolutionary, but simply evolutionary.  It had to happen to move forward.