Things You'll Need
Instructions
Put your PSP into USB mode by navigating in the main menu (XMB) to "Settings," then "USB connection." This allows the PS3 to see the PSP as a USB storage device.
Plug the small end of the mini-USB cable into the top of the PSP and plug the larger end of the cable into a USB port on the PS3.
Power on both the PSP and the PS3.
Go to the "Music" category on the XMB and select individual files or folders, or use "Select all" to transfer your entire library.
Press the "Triangle" button and select copy and select the PSP (or USB device) as the destination.