TonK said:
Nobody is 100% positive the JPN system will play US games...
The PSP supports region locking for titles, which limits which software may be played on each region's hardware. They have announced in interviews that the system will adopt the DVD regional lockout scheme; Japanese PSP hardware already has a R2 logo on its box. However, support for regional lockout does not necessarily mean it will be used for all software.
According to Sony, games for the PSP will at first be encoded as region-free. There will be no limitation as to what country's model can play what country's version of the game. This will open up the "portability" of the handheld, as well as enable gamers who buy a PSP game on holiday to play it on their native PSP. There has been some confusion over this, however, as the Japanese releases of titles such as Ridge Racers carry a Region 2 logo. It is traditional for handheld games consoles to carry no region locks; for example, the Nintendo Game Boy lineage.
It is expected that movies for the PSP will be region-locked, much as DVDs are.
So, if the companies wan't to block out region1 PSP's they can.
As a note, Ridge Racer DS is a port, remake of RidgeRacer64, the psp version is a new game, and new games are better then port remakes.
Another point of interest, the second screen on RRDS looks hideous.