I got the GPS reciever for PSP!

Damn dude, didn't you know (as with most GPS units) you need the software with the maps. ArmoJan

Yes, I realized that, but I couldn't find the software so I went ahead and bought the GPS first.  

I realized that, but I couldn't find the software so I went ahead and bought the GPS first.

The_Gunslinger_

It's only in Japan specifically because the map software (and Map sets) for the US is not available.  After all, this is exactly why you could not find the software.  You will either have to wait for the US version to be released (who knows if and when) or you should try to return it.