**NOTE** 'I have done this, and if you do the same, I am NOT responsible for any messups'
This is what happens when an iTrip (fm transmitter for iPod) and a PSP get together.
I got this idea when I was driving around with my wife. She owns an iPod mini with an iTrip.
I was jealous that she could listen to her music via the car stereo and change frequencies on the fly.
She also had the entire FM band at her disposal. That's 87.9Mhz to 107.9Mhz - over 100 frequencies to choose from.
Now, sure, I could go and get an FM transmitter to jack-in to my headphone jack, but then I've got this cumbersome thing hanging from my sexy PSP.
One idea was to gut a generic FM transmitter.
Most of those have switches to change the freqs, and I'd have to make a place for those switches on the exterior of the PSP.
That would take away from the clean look of the PSP
The plan is to marry the two so that the PSP still looks like a PSP, plus maintain the ability to change freqs on-the-go.
First thing: pre-planning
Take the time to plot it all out.
Next I opened her up. I won't bore you with the details on how to disassemble a PSP. You can find a tutorial about that elsewhere.
Then I played around with placement until resting on this spot under the WiFi/audio/memory stick daughterboard.
Next the pinout. (edit) The voltages do not have to be exactly 3.2. I was simply recording the stock voltages the iTrip operates on.
For those of you that can't read my chicken scratch...
1. audio Left
2. audio Right
3. audio GND
4. NC
5. +3.2VDC
6. GND
7. +3.0VDC
8. +2.8VDC
(edit) I've been getting a lot of e-mails asking for more info on the wiring, I hope this helps.
It wasn't a match made in heaven so...
I made room.
When it all fit, I reassembled and ran my wires.
During reassembly there were a few things that didn't make it.
(edit) This part is not a support structure its just a grounding plate/RF shield. My PSP works fine without it.
Now it's all back together. It works great. To turn on the iTrip I use a dummy headphone plug. This way the transmitter isn't on all the time.
To change freqs, toss in your iTrip CD. Go to "D:\Setup\US" and copy these files to a folder in your music directory on the PSP. I labeled mine "Change Freqs".
Now, just like the iPod I can change freqs any time I want.
All that's left to do is to tell you that charging or using WiFi have no adverse effects.
Finally... Rock out.
***Tutorial taken from
http://badacetechshow.com/psp_itrip.htm with permission***
MODDING PSP WITH ITRIP
good find 
Linear Mode
