[Cyclamen]

On a japanese PSP, you can play every game (they are not region specific), but you will be able to play **only** japanese UMD Videos, not american. Firmware isn't a problem, you can easily install every firmware you need since they are region free (speaking of which, try installing a homebrew firmware, which works better than the normal one). As for the power charger, both DS and PSP are supplied with a 110V only charger. So, either buy a transformer to make it usable with the north american voltage standard (it will cost you around 2500yen), or buy a USB charger (i got one for only 300yen!).