I don't think there's going to be any problems. I imported a PSP from Japan and compared the charger with the one that came with the US version. Voltage/amperage/polarity are the same.
Input: 100V-240V ~ 0.3A 50/60Hz
Output: 5V, 2A
The chargers were for the PSP-1000 series. Looking at the input voltage, seems like you can even use it in Europe, just need to change the plug.