For anyone who needs it, I founda link on how to make a Japanese account (so that you can DL the Prologue demo):
http://www.britishgaming.co...
Traditionally the Prologue and Concept discs have been relegated to Japan-only, but if it's available on the Japanese PlayStation store you simply have to make a Japanese login alias.
So to answer your question, it'll technically only be available in Japan, but you should theoretically be able to DL it from anywhere in the world as long as you sign into the Japanese store.
Slightly off-topic, since this is about the graphics. I know that Prologue is only a demo version, but thus far I'm highly unimpressed with the physics in the game. Even if you turn off all the assists, the cars don't do a lot of what real cars do. For me an arcade game like PGR4 does a better job of giving gamers the perception of physics without trying as hard at GT does.
Back to graphics, I'll be interested to see how GT5's Nurburgring turns out. That would be a great compar...