First you need to update to 6.60 OFW and the install the CFW. To update you can either do it yourself or you can do network update on the psp.
Heres how you do it. If your already on 6.60 OFW skip these steps. Also skip if you are going to do system update from the XMB. Just go ahead and update either way to
1. Download this :6.60 OFW - 6.Downloads - Sony PSP MODS and Hacks Forums and extract it and have it handy.
2. Now plug the psp into the usb on your computer and open the PSP folder and then the GAME folder and create a folder named UPDATE and put the 660 eboot in there.
3. Now exit out of the USB and go to the psp and go to GAME and run that update. That should put you on 6.60 OFW.
Now to install the CFW.
When you go back to the game folder on the psp delete the UPDATE folder I told you to make.
1. Download this:6.60ME-1.6 (OFW Version) - Downloads - Sony PSP MODS and Hacks Forums and extract that.
2. Place the "me_installer" into your "GAME" folder on your memory stick .
3. Then go run that on the psp like you did the update and you should be good to go.