If you're a fan of driving and homebrew, then you've probably heard about Deniska's Map This! application for the PSP. Combined with a compatible GPS receiver for the PSP, it can turn your handheld into a living map of your nearby environs.
Unfortunately, doing something that complicated takes time and knowledge that not everyone has. Well, Deniska's PSP Development Site has an in-depth tutorial for installing and using the GPS and the Map This! software, so you should have fewer problems getting your beloved PSP to transform into a personal navigation system.
The tutorial covers the basics of installing and setting up your own local map for your GPS system, talking about what you'll need to bring it all together, as well as the steps you'll have to take to get your local map into the GPS. The tutorial also explains how to set up your own GPS-enabled trips, once you have the entire thing put together.
If you have some time, and aren't afraid of a bunch of directions, you might want to see how it works for you. If you've got it all together, then you should be able to enjoy some pretty sweet GPS joyriding,
like what these guys are doing, when you're done.
Read:
PSPnavi: How to turn your PSP into a GPS Navigation System or a Map ViewerSource:
PSPUpdates