Darwin is definitely not a Microsoft product, but it's also definitely an Xbox 360 motion controller.
Motus Games' Darwin was officially unveiled this morning on their website, the light saber-esque controller snaps in two uses a number of sensors to track where it is. It does this, according to the company, without the use of the IR receiver that the Wii uses. Motus claims it is far more accurate than the Wii Remote. The device may also work on the Playstation 3, though the developers are being deliberately vague about that.