Using nothing more than a little fine soldering, it is possible to get your PSP to accept the data output from 3rd party GPS recievers from Holux, among others.
Like a lot of past PSP mods, this probably isn’t one for mere mortals: you’ll have to have a heavy dosing of leet skill to pull this one off, and be able to understand the gobbledegook that the custom executable throws up — although it will apparently work with Map This, a third party GPS and Map app for the PSP.
Nevertheless, it’s all there on the read link, so check it out if you dare.

More information [Deniska's]