HOW TO PUT WINDOWS XP ON YOUR PSP

This article will show you how:

Here are the steps:
1. Connect your PSP to your Pc using the usb cable.
2. Open "My Computer" on your Pc and make a note which Letter drive your PSP is connected to. For example, "G:"
3. On your PC go to download.com's download page
4. This should open a page to download, "PspWxp 1.02."
5. Click on "Download Now" to download the zip file containing Windows XP for your PSP.
6. Download it and save it to any location on your PC.
7. Open the zip file which will be called "pspWxp102.zip"
8. Double click on the "Install" .exe file.
9. Select the letter of the drive that your PSP is connected to.
10. Click "OK"
11. Click "Yes" to install it.
12. It will begin to transfer the files required to your PSP, which may take a few minutes.
13. Once it is complete a message will pop up saying "Finished Copying," so click "OK," to continue.
14. Disconnect your PSP from the PC.
15. Open the Internet Browser on the PSP
16. Enter - file:/pspWxp/index.htm - into the address bar.
17. Use it just like you would Windows on your PC.
18. Have fun
19. This little hack also works very well on Archos devices, especially the Archos 605 WiFi



Source:
http://www.wikihow.com/Put-Windows-XP-on-your-PSP