The gran turismo HD concept demo will be launched on the Playstation Store from the 24th of December 2006.

The details albeit in japanese are here

And more interestingly Yamauchi san also has posted his comments there saying that Gran turismo 5 is being given preference over gran turismo HD and he expects that to be released earlier.

Anyways lets be content with Santa yamauchi's gift of a demo this christmas. By the way its been quite some time since we have heard of that GT-Mobile... maybe its no more on cards for the PSP???