First off, this isn't some "official Microsoft support thing", so don't even go there.
But evidently one of the developers (Nick Randolph) presenting at ReMix Australia used a Nintendo Wii remote in some fashion with the Windows Phone 7 emulator.
The Wii remote uses Bluetooth to connect to devices and it's been shown to be very hackable, running on everything from a PC to the new iPad. So any trickery to get it to work on WP7 is easily in the realm of plausibility.
What is exactly being used for? We have no idea. Could be just for simulation, could be something more interesting. Either way, sounds like these developers are liking what they see. I mean, just look at how shocked Stan is in that second Tweet.