This is cool:
PSP-Spot -> Play PSP Media On Your TV VIA PS2!!!
Put Action Replay Evo or what ever that has the Media Player into the PS2. Start the Media Player. Hook up the USB to the PSP and into the PS2. Then start up the PSP go to USB MODE and BOOM! You got your Media files on the TV!
But I would guess this doesn’t work with UMD movies, which is what is really needed (some way to be able to play them on a larger screen than the PSP’s screen; key to UMD movie success, imho).