libWiiSharp v0.1 released by Leathl.

libWiiSharp is a Wii related .NET (2.0+) library.
It can be used with any .NET language to easily develop Wii related applications.

All public functions are documented and most should be pretty self-explanatory.
There are also some example applications that use libWiiSharp included.

http://wiibrew.org/wiki/LibWiiSharp