*thoughtfix*, as you have shown, pushing power up the USB port is trivial, and once the Nokia 770 becomes a USB host, any self powered hard drive like the Apple iPod can be connected to it...

However, this hard drive for the Sony PSP is itself USB host, allowing data to be pushed to any USB mass storage device (including the Nokia 770's RS-MMC card and the Sony PSP's Memory Stick Duo card).