This would be a nice little mod for you PSOne emulator lovers out there. If I had any do-it-yourself ability in me, I'd do this in a heartbeat.  Hope someone gets some use out of this.  Unless of course someone has already done something like this before :P

There's a video and some pics as well as instructions in this site.

http://www.acidmods.com/forum/index.php?topic=15108.0

Quote:Notes: The following mod requires you to solder to your PSP's Motherboard!
So if you don't know how to use a soldering iron I suggest you don't do this MOD.

This MOD is for the fat PSP, but you can do the same on the Slim.
Although I would never take my Slim apart. :P

This will not affect your PSP's normal play outside PS1 Games!
Everything will work like it should Joystick, D-Pad and all the buttons.