PSP-Maps is a homebrew application to bring Google Maps, Virtual Earth and Yahoo! Maps to the PSP with a simple interface. This program is not using the Google Maps API (except for address search), it is retrieving the images directly using the wireless connection.

You can search for an address, add/load favorites, or just move around on the map. There is also a local cache which allows you to browse the maps offline.

PSP-Maps is released under GPL so the source code is available.

http://www.neoflash.com/forum/index.php/topic,5293.0.html