Ok, so you want to make a wallpaper for your PSP. But what do you need?
1. Your going to need a image editing program. Now since I'm a designer, I have photoshop on my comp. But really you could do this with MS Paint.
2. You need some sort of image. Anything bigger than the standard size for the PSP, which is 480x272. So anything bigger than that and youre good to go.
3. Open that picture in your image editing program. Then use the crop/resize tool and size your wallpaper down to 480 wide x 272 tall.

Bam youre all done. The wallpaper is the right size and ready to be imported to your PSP.
If you have any questions let me know. I'll add a better description to this later.

Look this is an example of a picture made with MS Paint:



I made this just with some lines...
And some colors...

What format should the wallpaper be in ... mine is in JPG but when i put it in the PSP i cant find the file ... pls help

Try a BMP format

jpg works.

when u open your psp memory stick on your computer you should see a folder named " PICTURE " in caps. if u dont c one, make one. put all your pics/images in there. that should work

let me know if you still need help

I have had problems with JPG formats before though. I think if the size of the file is too large the PSP doesn't regonize it. At least that's what has happened with me...

where can i get a free program which will allow me to make my own psp wallpapers.

The best free program, which is GIMP. Its a little difficult to learn at first. It should be able to do anything you want for making wallpapers.