Want to add a GPS receiver to your PSP? Here's how:

1) First off, you got to get your hands on these things:

* Holux GPSlim236 ($100)
* Intec G6704 PSP Remote Control ($11). Alternatively you can rip the connector of your original remote control.
* USB (Mini B) cable ($5-10) (NOT the included USB power cable, buy another one)
* 1K 1/4watt resistor ($1)
* Electric tape ($2 roll)
* Multimeter (for checking the connector pins, alternatively you can use just a circuit made out of a low voltage bulb and a battery)
* Soldering iron
* Razor blade (for cutting and cleaning)

2) Next, cut the USB cable and PSP remote plug. Determine which goes to which connector pin and well, connect them (Don't worry, we included diagrams for you, shown below).
DIY PSP-GPS

3)The developer included a GPS program viewer to check if you installed it correctly, which could also be downloaded here.

Download: [GPS Viewer Program for PSP]

4) And lastly, the notes of the developer:
The source code is included in the zip...
Note, the program is written to work in kernel mode, so I doubt that it will work on 2+ fw..
Perhaps someone can look in to how to adjust it...

Use caution when connecting the wires, make sure all of them are carefully insulated. You don't want to short any of them, since this may brick your PSP or GPS device.
Also, GPSlim 236 spec says that the TXD voltage may range from 3.2 to 5 V, so 1K resistor may not be enough to lower the voltage in some cases. So buy a few resistors: 5k,3k,2k,1k and see if your circuit works with a bigger value resistor first..

Special thanks to Art and futaris for helpping me out with serial port comm problems...

Almost forgot a disclaimer: As always, I am not responsible for any damages.