Arcade joystick manufacturer Hori is making the ultimate Hatsune Miku: Project Diva accessory. They have an arcade style controller for Hatsune Miku: Project Diva Dreamy Theater 2nd.
So, to use this you have to plug your PSP with Hatsune Miku: Project Diva 2nd into your PS3 and connect Hori’s controller into the console. When everything is set up you have something like this video.
At 29,939 yen ($360) its only a little less than the price of a PlayStation 3 in Japan.