pes2008editing.blogspot.com
Jon Murphy today announced the XBOX 360 demo is coming tomorrow, like the PC and PS3 versions (which he announced a week ago).
He also said the PC demo will be available from around 1 AM CET on the official PES site (and probably lots of other mirror sites).
The PS3 version will be online from around 4 PM tomorrow, while the 360 versions is set for mid morning.