Here’s a cool article explaining the inner works behind the Wiimote. Of course, there’s a bunch of Wii hacks but this one really goes into depth with topics like USB HID.
Most people don’t know that the Wiimote communicates with the Wii via a Bluetooth wireless link. The Bluetooth controller is a Broadcom 2042 chip, which is designed to be used with devices which follow the Bluetooth Human Interface Device (HID) standard, such as keyboards and mice. The Bluetooth HID is directly based upon the USB HID standard, and much of the same documentation applies. The Wiimote is capable of transmitting huge amounts of data to the Wii (Nintendo just isn’t utilizing it’s capabilities thus far). But using the internal Bluetooth wireless link, you can connect your Wiimote to your PC (any OS), and use it with a wide range of applications already made for the Wiimote.