There are definitely easier hacks out there, but if you want to try your hand impressing your friends with GPS on
your PSP, check out the GPSP project. Some dude named Art adapted a Garmin to his PSP, and is running GPSP software
under LUAplayer on the v1.50 firmware. Or, you know, you could just get a Bluetooth GPS module and use it on your
smartphone, or something.