Exar’s Neo Geo Stick 2 for PS3, releasing July 16 in Japan. In addition to this, creator Exar is also releasing a PS3 version of its EXARSTICK with King of Fighters XII art.
The Neo Geo Stick 2 costs ¥5,229 ($54), and the EXARSTICK costs ¥6,279 ($64), though you should account for an extra $20 or so for shipping, should any of the import retailers offer it.
Both of these sticks are also available for Wii (the EXARSTICK in both Super Famicom colors and a Tatsunoko vs. Capcom theme), but I want to get one of these USB sticks for use as a PC controller. If that works. I don’t really know anything about PS3 controllers.