not sure if this was already announced by anyone but found this:
"We can only imagine what this currently useless piece of technology can do for the homebrew scene. A PSP manufacturer known as Neo has created a motion sensor you can click onto your lovely handheld, but you'd have to have the old PSP -- this thing won't work on the PSP-2000. It's available now, but finding it for sale is a bit more than a challenge. Maybe it's a prank, but we don't think so. A lot of weird do-it-yourself devices and softwares are out there for the PSP, after all.
So what would homebrew people make with this motion sensor? After a lengthy brainstorming section (waiting for coffee to drip), we decided the coolest use of the motion sensor would be a game where you play the leader in a majorette band and you have to throw the PSP into the air, making sure to twirl it a certain number of times before you catch it. If you miss catching it, you lose. For real. That would be a hardcore game, but like with a lot of motion sensing things, you might as well just go outside and do something."
I'd use it if it was cheap enough!!