PSPlorer is a file explorer for PSP:

The main functionalities:
– File exploration on the memory-stick, flash0, flash1 and umd
– copy, delete, move, rename of files and directories
– dump and securised flash of the NAND. WARNING, even if the flash has been tested on several PSP, the flash of the nandBackup
is still a risky thing. I won’t accept any responsabilities in case you brick your PSP.
– Umd backup
– USB connexion
– creation of new files and new directories
– file hex-edit
– file transfert from PSP to PSP via wifi

http://forums.qj.net/showthread.php?t=138693